• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.10
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• pp.725-732
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• 2017

Weight reduction is one of the important issues in the automotive industry and the development of internal combustion engines vehicles, future vehicles, and eco-friendly vehicles for improving fuel efficiency. The objective of this study is to investigate the improvement of driving performance by weight reduction and optimum design for a formula-type self-designed on-road vehicle. This study is divided into the four steps. Firstly, the engine room was replaced and designed with a lighter engine. Secondly, an optimization study was conducted to simplify and lighten the vehicle components with the design of the frame. Thirdly, the structure design was optimized and the suspension was analyzed with the design of the frame. Finally, the design of an upright and hub with reduced weight was carried out using lighter parts. As a result, we reduced the weight of the vehicle by 48.5kg compared to the previous year (19.5%) and increased the acceleration from 6.8 s to 5.8 s.s.

• Bulletin of the Society of Naval Architects of Korea
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• v.4 no.1
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• pp.49-54
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• 1967

The authors considered the effects of trim in the small coastal passenger boat upon resistance in this paper. Any change of trim no matter how small, necessarily produces some effect upon resistance. The relations between the resistance coefficients and trim were investigated through the towing test of the Model $MCI-P_1-65$, Korean Standardized Ship, GT 70 tons passenger boat in the gravitational tank. The Lines of the Model are given in Fig. 1. Principal dimensions and other characteristics vary with the trim in general. Those values varied with the trim for $MCI-P_1-65$ are tabulated in table 1. The resistance was measured at five conditions such as even keel, 0.0273L, (original designed trim) 0.0473L, 0.0663L, 0.0873L trim by the stern, fixing the displacement corresponding to the designed load water line. Model was made of wood in length of 3.5 feet coated with varnish, and without appendages. As the artificial turbulent stimulator, the sand strip method was used. The results of model towing tests, correcting to water temperature of $70^{\circ}F$, were expanded to full scale using the Schoenherr's friction formula and surface roughness allowance coefficient of 0.0004. The authors point out, the following results. 1) Optimum trim which gives the minimum resistance exists for every speed at constant displacement and each comes to the same value. For $MCI-P_1-65$ optimum trim is 0.0673L trim by the stern(Fig.4-The cross curves of the resistancecoefficients). 2) At constant displacement, when LCB(longitudinal position of center of buoyancy) varies with the trim, there exists optimum value of LCB which gives minimum resistance for every speed and each comes to the same value. For $MCI-P_1-65$ optimum position of LCB is 8%L aft from midship section (Fig.6).

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.1
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• pp.36-42
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• 2018

This paper considers the Marine Traffic Risk Assessment for fixed and moving targets, which threaten officers during a voyage. The Collision Risk Assessment Formula was calculated based on a dynamic ship domain considering the length, speed and maneuvering capability of a vessel. In particular, the Navigation Risk Assessment Model that is used to quantitatively index the effect of a ship's size, speed, etc. has been reviewed and improved using a hybrid combination of a vessel's dynamic area and the Collision Risk Assessment Formula. Accordingly, a new type of Marine Traffic Risk Assessment Model has been suggested giving consideration to the Speed Length Ratio, which was not sufficiently reflected in the existing Risk Assessment Model. The larger the Speed Length Ratio (dimensionless speed), the higher the CJ value. That is, the CJ value is presented well by the Speed Length Ratio. When the Speed Length Ratio is large, states ranging from [Caution], [Warning], [Dangerous] or [Very Dangerous] are presented from a greater distance than when the Speed Length Ratio is small. The results of this study, can be used for route and port development, including dangerous route avoidance, optimum route planning, breakwater width, bridge span, etc. as well as the development of costal navigation safety charts. This research is also applicable for the selection of optimum ship routing and the prevention of collisions for smart ships such as autonomous vessels.

• Journal of the Korean Society of Food Culture
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• v.15 no.1
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• pp.1-8
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• 2000

This study was to investigate the effects of concentration of malt extract in Sikhye manufacture on saccharification time, shapes of saccharified rice(the cooked rice) and sensory evaluation score of Sikhye. The optimum concentration of malt extract to reduce saccharification time and to keep desirable shapes of saccharified rice was 4 times (rice 24g, malt 28g and D.W. 240ml) as suitable as base composition formula(rice 6g, malt 7g and D.W. 240ml). The shapes of saccharified rice were influenced by the concentration of malt extract, the saccharification time and the shapes of steamed rice before saccharification. A good taste(softness) of Sikhye rice and the desirable shapes of saccharified rice were more suitable in the case of a small amount of unsaccharified starch than in the case of finishing saccharification. The optimum saccharification time to keep the desirable shapes of saccharified rice was 240min and also was desirable between 210 and 270min. To keep a good taste(softness) and the desirable shapes of saccharified rice, and to reduce the manufacturing time, it is desirable to in mass production of Sikhye add 3 times more water after making Sikhye in the ratio of rice 24g, malt 28g and water 240ml. In this case the whole amount will become 4 times as much as the original one.

• Magazine of the Korean Society of Agricultural Engineers
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• v.12 no.1
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• pp.1854-1860
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• 1970

Results of this study on the influence of percent passing of No. 200 sieve on soil compaction are as follows; 1. The higher maximum dry density of soil is, the lower optimum moisture content is. Maximum dry density is highest value and optimum moisture content is the lowest value in twocases that percents of No. 200 sieve are 30% in soils of which percents retained on No. 10 sieve are 5% and 10% respectively. 2. Maximum dry density increases according as uniformity coefficient increase. Maximum dry density is the highest when uniformity coefficient is approximately 300 in soil of which maximum diameter is 4.76mm. 3. Maximum dry density has a tendency to become large according as value of Cu Caincrease. Correlation between maximum dry density and $Log_{10}$(CuCa) shows straight line. 4. Maximum dry density increases according as n increase and reaches the peak when n equal 0.35 in condition that the index of talbot formula n is less than 0.35 in soil of which maximum diameter is 4.76mm. 5. Maximum dry density has a tendency to increase according as value of Cg $(Cg=\frac{P_{50}^2}{P_{10}{\times}{P_{200}}$) decrease.

• Journal of the Korean Applied Science and Technology
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• v.16 no.2
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• pp.171-177
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• 1999

The objectives of this study is to investigate the optimum reaction conditions and to identify the product formula in the synthesis of a silicone/acrylic resin that curing in moisture at room temperature. By the addition polymerization of monomers, n-butyl acrylate, methyl methacrylate, n-butyl methacrylate, and 3-methacryloxypropyltrimethoxysilane. a quarter polymer was obtained. Among various initiators investigated in this study, 2.2'-azobisisobutyronitrille was found to be the most suitable initiator. The optimum reaction conditions found in this study are 70 wt% of initial solvent amount, 120 minutes of dropping time, 3 times of initiator addition, $82{\sim}105^{\circ}C$ of reaction temperature, and 8 hrs of reaction time. Also, number average molecular weight of $11700{\sim}33100$ and molecular weight distribution of $1.81{\sim}3.44$ were obtained.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.7
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• pp.110-116
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• 1994

In this paper a Duty Effective Overlap Scanning method (DEOS) for the improvement of driving efficiency of LC displays which have the RMS voltage responding characteristics is proposed and new processing method of data signals for optimum application of this method is also proposed. Proposed method has a few advantages such as the increment of duty ratio the increment of driving power loaded on LC cell and the decrement of RMS voltage error rate caused by signal attenuation on electrodes composing of display when compared with the conventional method which is called as optimum voltage amplitude selection method. And also by adopting new data signal processing method which has 3 kinds of voltage levels additional advantage much improving crosstalk phenomenon which is the most serious problems of simple matrix structured display is obtained. For the characteristic estimation new mathematical representation for new overlap scanning method and data signal processing method are induced and defined. And by the defined formula and simulation the characteristics of the proposed method and the conventional method are compared and analyzed. As a result of estimation this new method being able to optimize the overlap rate of scan signal and using 3 levels of data signals has the characteristic which can improve the driving efficiency of LC displays.

• Elastomers and Composites
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• v.29 no.1
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• pp.18-29
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• 1994

The purpose of this study is to investigate reinforced effect between silica treated by coupling agents and rubber matrix under the configuration chemical bonds, and the effect of silica particles coated by organic polymers using aluminum chloride as the catalyst. In vulcanization characteristies were tested by Curastometer. The M-series vulcanizates were reached to the fastest optimum cure $time(t_{90})$ and R-series vulcanizates with the same formula had the shorted optimum cure times. Tensile characteristics measuring with a tensile tester revealed that the M-series vulcanizate was the best in the physical properties, such as tensile strength. In 100% modulus, however, the S-series vulcanizates appeared to be better than the other vulcanizates. Also, hardness showed the following order : S-series>R-series>M-series with the order of elongation R-series>M-series>S-series. In SEM test, shapes of chemical treated silicas were observed. The dispersion of filler in the SBR composite appeard uniformly. In RDS test for the dynamic characteristics, G' indicates that S-3 shows the highest value with the next order M-3>R-3, and the order of damping values are as followe: M-3>M-3>R-3.

• Journal of Pharmaceutical Investigation
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• v.28 no.4
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• pp.267-274
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• 1998

Biphenyl dimethyl dicarboxylate (DDB) has been used for the treatment of acute and chronic hepatitis. However, its poor solubility in water, $2.5\;{\mu}g/ml$, caused low bioavailability of the drug after its oral administration. In order to increase the dissolution of DDB in gastrointestinal tracts, consequently to increase the bioavailability of the drug, DDB tablet was prepared with solid dispersion of DDB with poloxamer 338 or 407 using a direct compression method. To improve the flowability of the solid dispersion, Aerosil was used as an adsorbent. The effect of formulation variables (poloxamer and Aerosil contents) on the dissolution rate of DDB from tablets was investigated using an analysis of variance. The dissolution rate of DDB from tablets was evaluated with KP II (paddle) method. The dissolution patterns of the drug from the tablet prepared with poloxamer 407 were affected significantly by the contents of poloxamers and Aerosil over the range employed, but those of the drug from the tablet prepared with poloxamer 338 were not. The optimum formulation of the DDB tablet, showed the same dissolution pattern as that of the reference, was obtained after polynomial equations of drug dissolution profiles for each formula were fitted to contour plots. The optimum formulation ratios of DDB:poloxamer 407:Aerosil were 1:2.5:2.5 and 1:5:5.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.11
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• pp.23-29
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• 2010

The principal factor determining an optimum design method for cathodic protection is finding the protection current for preventing the corrosion of existing, already laid pipe. Some factors currently used to test designs include the sizes and lengths of pipes, soil resistivity, and the coating damage rate. We believe this method and current formulae are not optimum due to the uncertainty of determining the coating damage rate and the corrosion protection current's density. This paper analyzes the amount of protection current obtained by performing a temporary current test using data describing existing laid pipe. We then propose determining the corrosion protection current by using the temporary current test after modifying the formula. In addition, we suggest a way to choose optimized cathodic protection and the process of design by executing the design and taking account of such factors as a site condition of 34km-long non-protected water supply pipe lines (stages I and II) in ${\bigcirc}{\bigcirc}$ region, climate, interferences, and durability.