• Ecology and Resilient Infrastructure
• /
• v.3 no.2
• /
• pp.100-109
• /
• 2016

Low impact development (LID) facilities are established for the purpose of restoring the natural hydrologic cycle as well as the removal of pollutants from stormwater runoff. Improved efficiency of LID facilities can be obtained through the optimized interaction of their major components (i.e., plant, soil, filter media, microorganisms, etc.). Therefore, this study was performed to evaluate the performances of LID facilities in terms of runoff and pollutant reduction and also to provide an optimal maintenance method. The monitoring was conducted on four LID technologies (e.g., bioretention, small wetlands, rain garden and tree box filter). The optimal SA/CA (facility surface area / catchment area) ratio for runoff reduction greater than 40% is determined to be 1 - 5%. Since runoff reduction affects the pollutant removal efficiency in LID facilities, SA/CA ratio is derived as an important factor in designing LID facilities. The LID facilities that are found to be effective in reducing stormwater runoff are in the following order: rain garden > tree box filter > bioretention> small wetland. Meanwhile, in terms of removal of particulate matter (TSS), the effectiveness of the facilities are in the following order: rain garden > tree box filter > small wetland > bioretention; rain gardens > tree box filter > bioretention > small wetland were determined for the removal of organic matter (COD, TOC), nutrients (TN, TP) and heavy metals (Cu, Pb, Cd, Zn). These results can be used as an important material for the design of LID facilities in runoff volume and pollutant reduction.

• Journal of Korean Society of Steel Construction
• /
• v.23 no.6
• /
• pp.647-657
• /
• 2011

This paper describes the moment capacity of flexural members with local buckling based on a series of FE and experiment results. Thin-walled flexural members undergo local, lateral-torsional, or interactive buckling according to the section geometries and lateral boundary conditions. Flexural members with large width-to-thickness ratios in the flanges or the web may undergo local buckling before lateral-torsional buckling. Local buckling has a negative effect on the flexural strength based on the lateral-torsional buckling of flexural members. This phenomenon should be considered in the estimation of the flexural strength of thin-walled sections. Flexural members with various width-to-thickness ratios in their flanges and web were analyzed. Initial imperfections in the local buckling mode, and residual stresses, were included in the FE analyses. Simple bending moment formulae for flexural members were proposed based on the FE and test results to account for local and lateral-torsional buckling. The proposed bending moment formulae for the thin-walled flexural members in the Direct Strength Method use the empirical strength formula and the grosssection modulus. The ultimate flexural strengths predicted by the proposed moment formulae were compared with the AISC (2005), Eurocode3 (2003), and Korean Highway Bridge Design Specifications (2010). The comparison showed that the proposed bending moment formulae can reasonably predict the ultimate moment capacity of thin-walled flexural members.

• The Korean Journal of Food And Nutrition
• /
• v.26 no.1
• /
• pp.22-28
• /
• 2013

The objectives of this study were to develop porridge with medicinal herbs and chicken breast meat and to find out the optimum mixing ratio. Several herb extracts such as Acanthopanacis senticosus, Rehmannia glutinosa, Disocorea japonica, and Poria cocos Wolf were used in the ratio of 2, 1, 1, and 1, respectively. The optimum processing condition for herbal chicken porridge was determined by a design expert program. Seventeen experimental points were selected, and herb extracts (82~101 g), chicken breast meat (30~50 g), and glutinous rice (40~60 g) were chosen as the independent variables. The measured responses were preference of taste, DPPH radical scavenging, SOD-like activity, and cost. The optimum formulation of herbal chicken porridge using the numerical analysis was set at herbal extracts (101 g), chicken breast meat (38.66 g), and glutinous rice (41.34 g) with a 0.714 desirability value. DPPH radical scavenging effect, preference of taste and the cost showed a linear model, whereas SOD-like activity showed a quadratic model indicating a higher interaction among the mixture. As a result of proximate composition of optimized herbal chicken porridge, the contents of moisture, carbohydrate, crude protein, crude lipid, and ash contents were 76.4, 9.0, 1.4, 0.5, and 1.6%, the calories of the porridge was 46.1 kcal/100 g.

• Korean Journal of Medicinal Crop Science
• /
• v.5 no.1
• /
• pp.67-71
• /
• 1997

Bupleurum falcatum is one of the oldest medicinal crop spontaneously generated as well as cultivated by man and successfully grown during the summer season in Korea. This study was conducted to examine the effect of planting density in the row spacing and hill spacing system using machine seeder on major agronomic traits, yield and labor saving. In 1993 and 1994, a spilt plot design was used with row spacing as the main plot and hill spacing as subplot. Labor saving efficency of the machine seeder reduced 96% than the hand seeding in sowing time required. Number of seeding stand increased, but stem height and number of nodes did not affect with different density in each row and hill spacing. There were reduced with narrow hill spacing on stem diameter, number of branches, shoot weight and root traits. There was no significant interaction between row and hill spacing for any major traits studied except shoot weight. Yield was more increase at 20cm than at 30cm row spacing. For these studies the optiomum density appears to be between drilling or 5cm hill spacing with 20cm row spacing. A highly significant positive correlation was appeared between number of seedling stand and root yield.

• Journal of Pharmaceutical Investigation
• /
• v.26 no.3
• /
• pp.187-192
• /
• 1996

The matrix tablet containing sodium alginate and $CaHPO_4$ can release drugs in a controlled fashion from hydrogel with gelling and swelling due to their interaction as water penetrates the matrices of the tablet. The purpose of this study was to evaluate release characteristics of the matrix tablet varying the amount of sodium alginate, $CaHPO_4$ and other excipients such as chitosan, hydroxypropyl methylcellulose (HPMC) and $Eudragit^{\circledR}$ RS100 in the simulated gastric and intestinal fluid. The practically soluble ibuprofen was used as a model drug. The release profiles of matrix tablet in the gastric fluid as a function of sodium alginate/$CaHPO_4$ ratio was not pronounced because of low solubility of drug and stability of alginate matrices. However, release rate of drug from the matrix tablet in the intestinal fluid was largely changed when sodium alginate/$CaHPO_4$ ratio was increased, suggesting that the ratio of sodium alginate/$CaHPO_4$ was an important factor to control the gelling and swelling of the matrix tablet. The incorporation of other excipients into the matrix tablet also influenced the release rate of drug. The chitosan and HPMC decreased the release rate of drug. No release of drug was occurred when $Eudragit^{\circledR}$ RS100 was added into the tablet. The retarded release of matrix tablet when excipients were added resulted from the hindrance of swelling and gelling of the matrix tablet containing sodium alginate and $CaHPO_4$. The hardness and bulk density of the matrix tablet was not correlated with release rate of drug in the study. From these findings, the ratio of sodium alginate and $CaHPO_4$ in the matrix tablet in addition to incorporation of excipients could be very important to control the release rate of drug in dosage form design.

• Science of Emotion and Sensibility
• /
• v.11 no.1
• /
• pp.39-56
• /
• 2008

Previous studies of music, user interface, and human-computer interaction have used sounds which include musical structure rather than real music. This study investigated whether real music affects objective and perceived usability. Silence, sound, and music conditions were compared in experiment 1 (kimchi refrigerator) and 2 (remote controller for air conditioner). Participants' performances of reaction time and accuracy, and the degree of subjective satisfaction were analyzed. The results showed that main effects on task performances were not different significantly; however, perceived usability of music condition was better than sound condition, which was better than silence condition. It means that musical user interface improves perceived usability while not interfering task performance. This study provides a basis of emotional and aesthetic effects of music in home appliances design, and can be applied to studies for the blind. More specific guideline for the musical user interface can be drafted if further studies consider more various tasks, context, musical structure and types for the appliances.

• Journal of Internet Computing and Services
• /
• v.2 no.2
• /
• pp.71-93
• /
• 2001

Commonly to design a database system. a conceptual database has to be designed and then it is transformed into a logical database schema prior to building a target database system. This paper proposes a method which transforms a Temporal Entity-Relationship Model(TERM) into a Temporal Object-Oriented Model(TOOM) to build an efficient database schema. I formalize the time concept in view of object versioning and specify the constraints required during transformation procedure. The proposed transformation method contributes to getting the logical temporal data from the conceptual temporal events Without any loss of semantics, Compared to other approaches of supporting various properties, this approach is more general and efficient because it is the semantically seamless transformation method by using the orthogonality of types of objects, semantics of relationships and constraints over roles.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.11 no.5
• /
• pp.1838-1844
• /
• 2010

In distance education, contents are to convey what to learn to learners, and the efficient quality assurance of contents is the very first step to the enhancement of distance education. Most studies of the quality assurance of contents have mostly centered around the development of evaluation tools, and few studies have ever focused on analysis of the quality of contents itself, since it's not easy to do that due to difficulties in the selection of evaluatees or of contents to be analyzed. The purpose of this study was to analyze the quality of 58 distance education contents of on-the-job training and another training for the acquisition of qualifications. As a result, the contents of the learning contents segment ranked first. Among the components of each segment, there was room for improvement in the level of learning and learning elements in the learning contents segment. In terms of instructional design, the quality of interaction components should be taken to another level to boost the quality of contents in this segment. The findings of the study are expected to give some suggestions about which parts of contents should be improved in quality from a perspective of contents developers or suppliers to enhance the overall quality of contents.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2018.06a
• /
• pp.62-62
• /
• 2018

Pt is still considered as one of the most active electrocatalysts for ORR in alkaline fuel cells. However, the high cost and scarcity of Pt hamper the widespread commercialization of fuel cells. As a strong candidate for the replacement of Pt catalyst, silver (Ag) has been extensively studied due to its high activity, abundance, and low cost. Ag is more stable than Pt in the pH range of 8~14 as the equilibrium potential of Ag/Ag+ being ${\approx}200mV$ higher than that of Pt/PtO. However, Ag is the overall catalytic activity of Ag for oxygen reduction reaction(ORR) is still not comparable to Pt catalyst since the surface Ag atoms are approximately 10 times less active than Pt atoms. Therefore, further enhancement in the ORR activity of Ag catalysts is necessary to be competitive with current cutting-edge Pt-based catalysts. We demonstrate the architectural design of Ag catalysts, synthesized using plasma discharge in liquid phase, for enhanced ORR kinetics in alkaline media. An attractive feature of this work is that the plasma status controlled via electric-field could form the Ag nanowires or dendrites without any chemical agents. The plasma reactor was made of a Teflon vessel with an inner diameter of 80 mm and a height of 80 mm, where a pair of tungsten(W) electrodes with a diameter of 2 mm was placed horizontally. The stock solutions were made by dissolving the 5-mM AgNO3 in DI water. For the synthesis of Agnanowires, the electricfield of 3.6kVcm-1 in a 200-ml AgNO3 aqueous solution was applied across the electrodes using a bipolar pulsed power supply(Kurita, Seisakusyo Co. Ltd). The repetition rate and pulse width were fixed at 30kHz and 2.0 us, respectively. The plasma discharge was carried out for a fixed reaction time of 60 min. In case of Ag nanodendrites, the electric field of 32kVcm-1 in a 200-ml AgNO3 aqueous solution was applied and other conditions were identical to the plasma discharge in water in terms of electrode configuration, repetition rate and discharge time. Using SEM and STEM, morphology of Ag nanowires and dendrites were investigated. With 3.6 kV/cm, Ag nanowire was obtained, while Ag dendrite was constructed with 32 kV/cm. The average diameter and legth of Ag nanowireses were 50 nm and 3.5 um, and thoes values of Ag dendrites were 40 nm and 3.0 um. As a results of XPS analysis, the surface defects in the Ag nanowires facilitated O2 incorporation into the surface region via the interaction between the oxygen and the electron cloud of the adjacent Ag atoms. The catalytic activity of Ag for oxygen reduction reaction(ORR) showed that the catalytic ORR activity of Ag nanowires are much better than Ag nanodendrites, and electron transfer number of Ag nanowires is similar to that of Pt (${\approx}4$).

• Science of Emotion and Sensibility
• /
• v.12 no.1
• /
• pp.55-64
• /
• 2009

Previous research has mainly investigated the characteristics of expertise by using typical and routine tasks. This research to overcome these limitations included non-routine task situations and observed expert and novice pilots' situation awareness (SA) performance in routine and non-routine situations. Additionally, whether the ability to aware or perceive the environmental information in limited time varies with the level of expertise was tested. To this end, $2^*2^*2$ mixed factorial design was employed, including expertise (novice/expert) as a between-subjects variable and normality of fight situation (routine/non-routine) and stimulus display time (long/short) as within-subjects variables. As results, there was no performance difference in routine situations between experts and novices, while experts significantly outperformed novices in non-routine situations. When the display time became shorter, overall SA accuracy was decreased for both experts and novices, whereas experts' performance remained significantly higher than novices in short and long conditions. When we examined the interaction between the normality of fight situation and stimulus display time, there was no difference between experts and novices in routine situations for both short and long conditions. In non-routine situations, however, experts' SA accuracy was significantly higher than novices both in short and long conditions. Overall, non-routineness of flight situation does not have any impact on SA performance of experts, while it has a critical impact on SA performance of novices.