• Korean Journal of Construction Engineering and Management
• /
• v.14 no.2
• /
• pp.96-107
• /
• 2013

Tower crane hoisting plan is one of the key element for the success of entire High-Rise Building construction. Hoisting time is the basic factor to appropriate hoisting plan which need to the hoisting load estimate and tower crane selection. With this reason, accurate hoisting time is needed to the proper hoisting plan. The current hoisting time estimation for High-Rise Building focus on the hoisting cycle time estimation with historical data. However, this method underestimated the external influences like environmental factor. Thus, this paper aims to develop the hoisting time estimation model with discrete event simulation which include the wind influences with certain height. According to the simulation result, the hoisting time which applied wind influence is increasing with height growth. Because of the high speed wind, the upper area of building has more operation delay time than the mechanical operation time. Seoul, the research area, has the most fastest wind speed on April and the least on October. Due to these differences of wind speed, the hoisting time is estimated with significant differences between April and October. This hosting time estimation model would be used for estimating the influence of wind. Moreover, this could apply to make the realistic hoisting plan.

• Korean Journal of Environment and Ecology
• /
• v.20 no.4
• /
• pp.425-435
• /
• 2006

The objectives of this research were to investigate the drought resistance as well as the growth of Wisteria floribunda seedlings with the soil water conditions. The seedlings for the research were grown in pots with strict water content control on a frame located outdoors. During the experiments, the soil water contents were adjusted to 5, 10, 20, 30, 40, 50, 60, and 70%. In addition, the effects of Rhizobium inoculation on the growth of seedlings were investigated. The experimental results are summarized as follows: 1. The seedlings in the pots with 5% soil water content withered to death due to the water stress. Withering or any distinct growth was not observed from the seedlings in the 10% soil water content. It can be inferred from these results that about 5% of soil water content is the wilting point of W. floribunda seedlings and about 10% is the critical soil water content of its growth in this experiment soils. Therefore, it seems that W. floribunda possesses a good drought resistance. 2. From the analyses of the main growth parameters such as stem elongation, diameter growth, leaf area growth and total dry weight, it was found that the seedling growth can be improved with increasing soil water contents. The relation between each growth parameter(Y) and the soil water contents(W) was well described by a quadratic equation, $Y=a+bW+cW^2$. 3. In soil water contents higher than 20%, the seedling growth(Y) was remarkable along with-its extended growing period, and related to the growing period(D) by a quadratic equation, $Y=a+bD+cD^2$. 4. The artificial inoculation of Rhizobiun promoted the growth of Wisteria floribunda seedlings. 5. Rhizobium was found to be more readily inoculated and to form more root nodules compared to seedlings grown in higher soil water contents.

• Korean Journal of Agricultural Science
• /
• v.10 no.1
• /
• pp.118-128
• /
• 1983

Simulation model of natural air grain drying was discussed and modified to predict the changes of grain moisture content and dry matter loss of rough rice drying. The modified simulation model was then validated using actual test data. A series of simulated drying tests using official weather data for 15 years from Beaumont, Texas, was taken to make minimum airflow rate and maximum bed depth of rough rice drying by natural air, under different conditions of initial moisture content of rough rice, airflow rate and harvest date.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.21 no.1
• /
• pp.35-42
• /
• 1976

In Korea, two types of rice varieties are being cultivated widely, Japonica and Japonica-Indica cross. Generally speaking, the latter shows weak cold tolerance than the former and so brought about many problems in cultural practices. This study was conducted to investigate the effect . of various temperature conditions on rice seedlings growth, especially the contents of chlorophyll and the percentage of nitrogen. And the result obtained indicated the varieties of Japonica-Indica intend to weak cold tolerance than Japonica varieties.

• Weed & Turfgrass Science
• /
• v.1 no.4
• /
• pp.18-23
• /
• 2012

To determine the effect of winter green manure crops for tillage and no-tillage organic pepper cultivation in plastic film house, five different green manure crops were cultivated during winter season. In nutrition composition of green manure crops, total nitrogen contents were higher in Vicia hirsuta and Vicia angustifolia than any other crops. The average dry weights of green manure crops were 8.3 ton per ha in tillage and 7.0 ton per ha in no-tillage, among green manure crops that of Secale cereale was the highest. Fertilizer supply was depended on the biomass of the cultivated green manure crops and nutrition contents, total nitrogen supply of V. angustifolia was 226 kg and that of S. cereale was 251 kg per ha in tillage field. In no-tillage field, N-supply of V. angustifolia was 197 kg and that of S. cereale was 222 kg per ha. In yield components of red pepper, fruit numbers per plant were 55.5 in green manure crop tillage and 37.0 in no-tillage cultivation. Among green manure crops, the yield of dried red pepper was the highest for V. angustifolia in both green manure crop tillage and no-tillage cultivation.

• Applied Chemistry for Engineering
• /
• v.16 no.6
• /
• pp.809-814
• /
• 2005

In this work, the thermal properties of epoxy coating system on the liner plate in the containment structure of nuclear power plants had been examined by irradiation and design basis accident (DBA) conditions. The effect of immersion in hot water on adhesion strength of the coating system had been also studied. The glass transition temperature ($T_g$) and thermal stability of ET-5290/carbon steel A 32 epoxy coating systems were measured by DSC and TGA analyses, respectively. Contact angle measurements were used to determine the effect of immersion on the surface energetics of epoxy coating system, with a viewpoint of surface free energy. Adhesion tests were also executed to evaluate the adhesion strength at interfaces between carbon steel plate and epoxy resins. As a result, it was found that the irradiation led to an improvement of internal crosslinked structure in cured epoxy systems, resulting in significantly increasing the thermal stability, as well as the $T_g$. Also, the immersion in hot water made a role in the post-curing of epoxy resins and increased the mechanical interlocking of the network system, resulting in increasing the adhesion strength of the epoxy coating system.

• Korean Journal of Plant Resources
• /
• v.12 no.4
• /
• pp.269-275
• /
• 1999

For the purpose of sweet potato varietal improvement, yulmi, shinyulmi, gunmi, hongmi, and seonmi, whose source and sink are different, were cultivated at different planting densities, and then defoliation at initial stage of tuberous root weight increase on the relation of source and sink was observed as follows. The response of stem and leaf and tuberous root weight by planting density and defoliation rate of sweet potato varieties was different. Stem and leaf weight per m$^2$ increased along with dense planting by the following order; shinyulmi> seonmi> hongmi> gunmi> yulmi. Tuberous root number per m$^2$ was the most at 75$\times$20cm planting density, showing seonmi the most number. The number of stem and leaf and tuberous root increased along with the lowered rate of defoliation. In case of 75$\times$10cm and 75$\times$20cm planting density, tuberous root weight increased by increase of stem and leaf weight up to 50% defoliation and the difference of stem and leaf and tuberous root number was low as defoliation rate increases. The tuberous root and total dry weight matter was the most at 75$\times$20cm planting density. The increase and decrease of source synchronized with those of sink at 75$\times$10cm and 75$\times$20cm, however the relationship occurred less at 75$\times$30cm.

• The Journal of the Korea Contents Association
• /
• v.19 no.1
• /
• pp.404-412
• /
• 2019

The purpose of this study is to develop the usability evaluation contents based on the needs of different stakeholder's related to the usability of the product, and to derive the design direction and apply it as the evaluation standard by applying the product design based on the results. I created a stakeholder map for a fire detector product and identified stakeholders related to usability. Based on 3 factors(Physical, cognitive, emotional) of the usability evaluation, I conducted survey on the building users and the building managers who have different requirements. There are 12 directions (ease of installation, durability, maintainability, additional functionality, effectiveness, attractiveness, visibility, consistency of information, environmental harmony, consistency, Image suitability, reliability). Through weighted analysis of three usability evaluation factors, I found factors were ranked in the same order of importance, but they were different in importance figure. Based on the results of the survey, overall product usability aspects were improved but effectiveness and environmental coordination aspects needed to be improved.

• Journal of Conservation Science
• /
• v.35 no.3
• /
• pp.217-225
• /
• 2019

The chimi(ridge-end tile) of Wangheungsa temple is the oldest in our country. The upper part of the chimi was excavated from the southern side of Wangheungsa temple and the lower part from the northern side. These parts are considered to be portions of the same chimi, because they are similar in shape and are excavated from two sides of the same temple structure. However, the original shape of the chimi cannot be determined owing to substantial deterioration. Hence, in this study, replicas of the deteriorated chimi portions of Wangheungsa temple were fabricated by employing 3D scanning technology and the computer numerical control machining method. While observing the bending phenomenon of the chimi, the proposed model was warped realistically on the basis of the bending direction of the actual chimi. Consequently, the restoration process was modified several times. The results indicated that no gaps can be found between the upper and lower parts, and the corresponding patterns connect naturally. Furthermore, the proposed method is contactless, safe, operable, reproducible, and appropriate for restoration of artifacts. Additionally, the modeling data is semi-permanent. Hence, if modelling data is appropriately applied as per the characteristics of artifacts, it can be utilized in various fields such as virtual exhibitions, hands-on exhibitions, cultural heritage restoration, and production of teaching aids and souvenirs.

• Journal of the Korean Institute of Traditional Landscape Architecture
• /
• v.36 no.4
• /
• pp.70-79
• /
• 2018

This study would suggest a measure for the improvement of the commentary program on the building concentration area of Changdeokgung Palace. In the process of the survey, the researcher attended the commentary site and tape-recorded commentaries two times. The researcher conducted an analysis of the times and contents of the tape-recorded commentaries and evaluated their appropriateness, including historicity and connectivity to the site. In addition, the researcher figured out the commentaries and the visitors' movements through drawings and field surveys and analyzed the locations and conditions of the main facilities. Through a field survey and analysis, it was found out that the commentaries included the facts and anecdotes about the buildings, the related figures and history. However, it was found out that there were very insufficient commentaries on the buildings arranged according to the commentary movements, the outside space, in particular, the traditional landscape facilities. In addition, it was found out that there are areas that would need commentaries and opening for viewing. A proposal for the improvement of the commentary program was drawn up based on the analysis. New commentary points were added, and the commentaries of the outside space of the area and the traditional landscape facilities could improve through modifying the existing commentaries. With the proposal for improvement, the time required was calculated through reading aloud at a speed the same as the existing commentary speed. Through this, it was found out that the proposal for improvement could be implemented within one hour, the same as the present commentary program. This study has a significance that it provided a measure for practical improvement that could provide the visitors with quality commentary information and more interesting experience.