• Journal of the Korea Concrete Institute
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• v.18 no.6 s.96
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• pp.793-800
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• 2006

This paper reports test results to assess the influence of superplasticizers and different admixture on the flow and compressive strength development of cementless mortar using developed hwangtoh binder. Test specimens were classified into four groups: series for I the mixing ratio of superplasticizers, series II for a kind and replacement level of admixtures according to the variation of water/hwangtoh binder ratio, series III for the specific surface area and replacement level of ground granulated blast-furnace slag and series IV for the replacement level of powered superplasticizer agent developed to improve slump loss of concrete. The proper replacement level of each admixture is proposed for enhancement the flow and compressive strength of the hwangtoh binder mortar.

• Journal of the Korean Society of Safety
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• v.21 no.1 s.73
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• pp.133-140
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• 2006

According to Tokyo protocol which suggests the prevention of global environmental pollution, Korean government establishes the standard of architectural materials emission consistency with best effort to decrease the environmental pollution. But many current architectural materials which are used for constructing and remodeling buildings are composed of a variety of chemicals. These include stimuli bad for the residents' health and safety and harmful discharged air polluting substances such as volatile organic compounds(TVOCs) and formaldehyde(HCHO) that in tern include a variety of carcinogen substances. These discharged substances are also researched into inducing 'sick building syndrome' which induces headache, dizziness, vomiting and concentration failure among residents. But the standard of architectural materials according to the Korean apartment provision is limited to emission factors: HCHO and TVOCs. So the aim of this study is to present a standard of functional material's emission consistency about TVOCs including glues and paints, and a certification grade for green building by instituting a materials standard for green building which has consideration for the residents' safety.

• Journal of the Korea Concrete Institute
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• v.23 no.6
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• pp.765-772
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• 2011

The present study summarizes a series of compressive tests on concrete cylinder in order to examine the stressstrain relationship of alkali-activated (AA) slag concrete. The compressive strength and unit weight of concrete tested ranged from 8.6 MPa to 42.2 MPa and from $2,186kg/m^3$ to $2,343kg/m^3$, respectively. A mathematical equation representing the complete stress-strain curve was developed based on test results recorded from 34 concrete specimens. The modulus of elasticity, strain at peak stress, slopes of ascending and descending branches of stress-strain curves were generalized as a function of compressive strength and unit weight of concrete. The mean and standard deviation of the coefficient of variance between measured and predicted curves were 6.9% and 2.6%, respectively. This indicates that the stress-strain relationship of AA slag concrete is represented properly with more accuracy in the proposed model than in some other available models for ordinary portland cement (OPC) concrete.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.10
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• pp.1485-1490
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• 2013

The demonstration project of the electrical grid for Smart grid is progressed, the smart digital appliances AV technology, Smart home energy management technology charging the management function of complex energy for the automation management of air conditioning and heating, humidity and air, the health care technology charging the design of housing for the elderly and disabled and the measurement of individual bio information, and the Smart home security technology dealing with the biometric security and motion sensors, etc. have been studied. The power monitoring terminal which uses a variety of wired and wireless networks and protocol is the target additionally to be considered in addition to the security vulnerabilities that was occurred in the existing terminal. In this research paper, the author analyzes the cryptographic techniques corresponding to the smart meter occurred by the problems that are exposed on the outside which are vulnerable to physical attacks, and intends to propose the design of the security systems for the Smart meter terminal being able to maximize the efficiency of the terminal.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.4 no.1
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• pp.10-17
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• 2001

Purpose: We measured anti-H. pylori IgG in Korean elementary school children living in Shinchon area of Seoul, Korea to evaluate the influence of environmental living standards on H. pylori infection. Methods: IgG antibodies to H. pylori were measured in plasma using a commercial ELISA kit (GAP IgG Helicobacter pylori, Bio-Rad Laboratories Inc., Hercules, CA, USA). Information on environmental status such as place of birth, parental income, type of housing, number of persons in the household, parents' occupation, family history of peptic ulcer disease and gastric cancer was obtained. Statistical analysis was done by Chi-square and logistic regression test using SPSS $7.0^{TM}$ for Windows. Results: Study subjects consisted of 571 children, and the age distribution ranged from 6.0 to 13.6 years with a mean of $9.6{\pm}1.8$ years. Male-to-female ratio was 1.1:1. The seropositive rates of H. pylori infection ranged from 10.4% in children aged 6 years to 30.9% in 12 year-old group, overall 16.8%. The prevalence of H. pylori infection progressively increased with age, but there was no significant difference in seropositive rates among children in different age groups (p=0.06). Seropositive rates of anti-H. pylori IgG on the basis of gender, place of birth, parental income, type of housing, parents' occupation, family history of peptic ulcer disease and gastric cancer showed no statistically significant difference. Interestingly, however, seropositive rate of anti-H. pylori IgG showed statistical significance in relation to number of persons in the household (p=0.003; Odds ratio 1.50 by logistic regression test). Conclusion: These results suggest that number of persons in the household is the most important factor among environmental living standards, and that risk of H. pylori infection increases by increment of 1.5 times as the number of persons in the household increases by one.

• Journal of Animal Science and Technology
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• v.44 no.1
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• pp.135-144
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• 2002

An experiment was conducted to evaluate a ventilation system, which was devised to encourage farmers to use the enclosed growing and finishing pig housing system. A roof-air-entry ventilation system in winter and a side-wall-air-entry system in summer were evaluated. Air flow rate on the floor level which is the low part of pen and the living area of pigs in the enclosed growing and finishing pig house during winter was measured at 0 to 0.19 m/s at the minimum ventilation efficiency of 1,440 $m^{3}/h$. During summer the air flow rate was detected at 0.07 to 0.42 m/s at the maximum ventilation efficiency of 24,000 $m^{3}/h$. Therefore, it is concluded that the side-wall ventilation system is suitable for growing and finishing pigs in the enclosed house during the days of mid-summer and the roof-ventilation system was suitable during the coldest days of mid-winter. In addition, although the enclosed pig house has the system in which air exhausts through only one side wall, air should enter through both-side walls for the better ventilation performance.

• Journal of the Korean Wood Science and Technology
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• v.46 no.1
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• pp.10-16
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• 2018

Lindera erythrocarpa is a less utilized species in Korea although that it has straight stem and it grows up to 40 cm in diameter. A proper kiln-dry schedule is required in advance to utilize an unknown species. Terazwa's quick oven-dry method was used to find it and which was confirmed by drying 25 mm thick boards in a kiln. The average green moisture content and the average green specific gravity of Lindera erythrocarpa are 72.3% and 0.53, respectively. Prospective kiln-drying conditions obtained by Terazwa's quick oven-dry method are a initial dry-bulb temperature of $50^{\circ}C$, a initial wet-bulb depression of $4^{\circ}C$ and a final dry-bulb temperature of $75^{\circ}C$, which are in a good agreement with USDA FPL kiln-dry schedule of T5-D4. 25 mm thick boards dried in a kiln with T5-D4 kiln-dry schedule did not have any severe drying defects such as honycombing and warping. A severer kiln-dry schedule of T8-C5 was developed and applied to another kiln-drying run to confirm it.

• Korean journal of communication and information
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• v.32
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• pp.247-293
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• 2006

It is an aim of this study to analyze a relation between modern medicine advertisements and body. Recently the academic world has discussed how comes it that the modernity had been formed. This trend is remarkable in the field of the history of everyday life. Because everyday life is connected with people's vivid experience. Especially in modern advertising it is in existence such as popular culture, consumer culture, sexuality, family, food, clothing and housing, disease. Since modern times the body has been reorganized into a new shape. Namely the premodern body that had been regulated by a status system is changed into modern body that have to form itself after the customs and values. We analyzed medicine advertisements in the early modern times and hoped to explain how modern people had understood their body. We applied Foucault's theory of discourse as a methodology. As a result of research, we came to the conclusion that there were several rules in the texts of medicine advertisements, which had formed a modern subject of pain. There was a disciplinary power such as a internalization of clinical eyes, self-watch in medicine advertisements. These advertisements contributed to the formation of subject of pain and related to the state power.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.11
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• pp.951-956
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• 2014

Steady-state thermal analysis was performed on a thermal equivalent circuit to determine the heat generation during operation of an interior permanent magnet synchronous motor (IPMSM). New machines must be compact and light and produce high torque density under extreme environmental conditions. Thermal analysis of an IPMSM is particularly important because excessive heat generated from the core and magnet reduces the IPMSM's output and has adverse effects on the durability. Therefore, steady-state thermal analysis of an IPMSM was performed for changes in the design variables using a thermal equivalent circuit. The changed variables were the axis length and thickness of the housing. The results of this method were compared with those of the finite element method to verify the accuracy and reliability.

• Journal of the Korean Recycled Construction Resources Institute
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• v.4 no.4
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• pp.388-395
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• 2016

This paper explores the photocatalytic sensitivity of cement mortar incorporated with recycled $TiO_2$ from waste water sludge. Basically, $TiO_2$ cluster sank down slowly to the bottom of cement mortar specimen before setting and hardening process. This leads the mismatch of $TiO_2$ concentration on the top and the bottom faces of a specimen. This poorly dispersed $TiO_2$-cement mortar naturally exhibits poor NOx removal efficiency especially on the top of cementitious structure. In architectural engineering application such as building or housing structures, one can simply filp over from the bottom so that more $TiO_2$ concentrated surface can be placed outward into the air. However, in highway pavement case, this could not be applicable due to in-situ installation of concrete pavement. Hence, the dispersion of $TiO_2$ cluster inside the cementitous material is getting important issue onto road construction application. To elaborate this issue, according to our results, silica fume, high-ranged water reducer, viscosity agent, blast furnace slag were not enhanced much of dispersion characteristics of $TiO_2$ cluster. The combination of foaming agent and accelerator of hardening with viscosity agent and small grain size of fine aggregate may help the dispersion of $TiO_2$ inside cementitious materials. Even though the enhanced dispersion were applied to the specimen, NOx removal efficiency doest not change much for the top surface of the specimen. This concurrently affected by the presence of tiny air voids and the dispersion of $TiO_2$ in that these voids could easily adsorbed NOx gas with the aid of large surface area.