• Journal of Mechanical Science and Technology
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• v.19 no.11
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• pp.2077-2081
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• 2005

A symmetry breaking nonlinear fluid flow in a two-dimensional wall-driven square cavity taking symmetric boundary condition after some transients has been investigated numerically. It has been shown that the symmetry breaking critical Reynolds number is dependent on the time history of the boundary condition. The cavity has at least three stable steady state solutions for Re=300-375, and two stable solutions if Re>400. Also, it has also been showed that a particular solution among several possible solutions can be obtained by a controlled boundary condition.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.40 no.3
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• pp.1-6
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• 2017

Process capability is well known in quality control literatures. Process capability refers to the uniformity of the process. Obviously, the variability in the process is a measure of the uniformity of output. It is customary to take the 6-sigma spread in the distribution of the product quality characteristic as a measure of process capability. However there is no reference of process capability when maximum material condition is applied to datum and position tolerance in GD&T (Geometric Dimensioning and Tolerancing). If there is no material condition in datum and position tolerance, process capability can be calculated as usual. If there is a material condition in a feature control frame, bonus tolerance is permissible. Bonus tolerance is an additional tolerance for a geometric control. Whenever a geometric tolerance is applied to a feature of size, and it contains an maximum material condition (or least material condition) modifier in the tolerance portion of the feature control frame, a bonus tolerance is permissible. When the maximum material condition modifier is used in the tolerance portion of the feature control frame, it means that the stated tolerance applies when the feature of size is at its maximum material condition. When actual mating size of the feature of size departs from maximum material condition (towards least material condition), an increase in the stated tolerance-equal to the amount of the departure-is permitted. This increase, or extra tolerance, is called the bonus tolerance. Another type of bonus tolerance is datum shift. Datum shift is similar to bonus tolerance. Like bonus tolerance, datum shift is an additional tolerance that is available under certain conditions. Therefore we try to propose how to calculate process capability index of position tolerance when maximum material condition is applied to datum and position tolerance.

• Bulletin of the Korean Chemical Society
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• v.27 no.8
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• pp.1145-1148
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• 2006

Excitability is one of the basic and fundamental mechanisms utilized for signal transmission in living organisms. With reference to the condition by Marek and the condition by Schneider, we found a condition in which excitability with similar shapes can appear by chemical and electric perturbation. Our condition is constructed with 3 chemical channels and 1 electric channel, and can be used as a condition for a chemical spiking neuron and as a unit of a chemical spiking neural network.

• Journal of Advanced Research in Ocean Engineering
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• v.4 no.2
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• pp.53-65
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• 2018

The load condition significantly influences ship maneuverability in calm water. In this research, the effect of the load condition on turning performance of a very large crude oil carrier (VLCC) sailing in adverse weather conditions is investigated by an MMG-based maneuvering simulation method. The relative drift direction of the ship in turning to the wave direction is $20^{\circ}-30^{\circ}$ in ballast load condition (NB) and full load condition (DF) with a rudder angle $35^{\circ}$ and almost constant for any wind (wave) directions. The drifting displacement in turning under NB becomes larger than that under DF at the same environmental condition. Advance $A_d$ and tactical diameter $D_t$ become significantly small with an increasing Beaufort scale in head wind and waves when approaching, although $A_d$ and $D_t$ are almost constant in following wind and waves. In beam wind and waves, the tendency depends on the plus and minus of the rudder angle.

• Smart Structures and Systems
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• v.15 no.3
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• pp.751-767
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• 2015

A new procedure is proposed for assessing probabilistic condition of structures considering effect of measured data uncertainty. In this procedure, multiple Finite Element (FE) models are identified by using weighting vectors that represent the uncertainty conditions of measured data. The distribution of structural parameters is analysed using a Principal Component Analysis (PCA) in relation to uncertainty conditions, and the identified models are classified into groups according to their similarity by using a K-means method. The condition of a structure is then assessed probabilistically using FE models in the classified groups, each of which represents specific uncertainty condition of measured data. Yeondae bridge, a steel-box girder expressway bridge in Korea, is used as an illustrative example. Probabilistic condition of the bridge is evaluated by the distribution of load rating factors obtained using multiple FE models. The numerical example shows that the proposed method can quantify uncertainty of measured data and subsequently evaluate efficiently the probabilistic condition of bridges.

• Corrosion Science and Technology
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• v.3 no.4
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• pp.166-171
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• 2004

Recent developments in Bridge Management Systems (BMS) and in Life-Cycle Cost (LCC) of bridges, have raised the need for evaluation procedure of future condition (Deterioration) of a bridge. Predicting future deterioration is not an easy task due to limited past data to extrapolate from and also due to difficulty in measuring actual deterioration such as section loss of steel on an actual steel bridge. Also, increase in live load and reduction of resistance are random variables, thus a probabilistic approach should be adopted for determining the future deterioration. Due to difficulties in evaluation of future deterioration on steel bridges, accepting uncertainties within a reasonable error, a deterministic procedure using bridge condition rating can be a useful tool for projection of future condition of bridges to identify repair and maintenance needs. The object of this paper is to determine applicability of evaluating deterioration of steel bridge components based on Bridge condition ratings. Bridge condition ratings of bridge components show wide variation for bridges of same age and does not directly correlate well with the age of the bridge and/or deterioration of the bridge. High uncertainty can be reduced by breaking down the rating and by sensitivity analysis. From refined condition rating data, generalized deterioration profile of structures based on age can be derived. Examples are shown for sample bridges in USA. Approximately, 3,000 short to medium span steel bridges were listed in the inventory database. Results show wide variation of rating factors but by subdividing the Bridge condition ratings for various categories general deterioration profiles of steel bridges can be determined.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.3423-3428
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• 2007

This paper shows that inlet humidity condition at cathode side is one of dominant parameters affecting the performance of PEMFC. To investigate effects of inlet humidity condition, the performance measurements were conducted for a single PEMFC with two operating variables : cathode relative humidity and dry condition in anode dry. The fuel cell employed for the experiments is a unit PEMFC with a 25$Cm^2$, Nafion$^(R)$112 membrane. As a result of this study, the cell performance is getting higher by increasing inlet humidity condition at cathode side. The cell performance is different from each operating temperature an it has maximum30% higher than dry condition at 60$^{\circ}C$ operating temperature with 80% relative humidity.

• The Mathematical Education
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• v.48 no.3
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• pp.287-302
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• 2009

This study investigated how 5th grade students found and understood triangle congruence conditions (SSS, SAS, ASA). In particular, this study focused on children's processes of discovering triangle congruence conditions and the obstacles which they encountered in the process of making sense of these conditions. Our data indicates that inquiring the cases in which less than three factors of triangle are given is helpful for children to guess triangle congruence conditions and understand the minimal characteristic of these conditions. And the degree of difficulty of discovering each congruence condition is different. Children discovered SAS condition and ASA condition easily, but it was hard for them to discover and understand that SSS was also a triangle congruence condition because they connected the length of a given side with the use of a scaled ruler not a compass.

• Journal of the Korean Home Economics Association
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• v.42 no.10 s.200
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• pp.91-104
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• 2004

The purpose of this study was to examine the differences of clothing microclimates and the subjective sensations according to age, gender and clothing weight for $19^{\circ}C$ air temperature. This study was done to gain fundamental data related to saving heating energy and to improve health through wearing underwear (long johns) in lower indoor temperatures. The subjects were divided into four groups (6 young males, 5 young females, 6 old males, 6 old females), and our experiment consisted of three conditions; the first condition was wearing long underwear in $19^{\circ}C$ air (19CUW condition); the second condition was without wearing long underwear in $19^{\circ}C$ air (19C condition); and the third condition was without wearing underwear in $24^{\circ}C$ air (24C condition). The experiment showed that the clothing microclimate temperature and humidity was the lowest in the 19C condition and the highest in the 24C condition irrespective of age and gender. The clothing microclimate in the 19CUW condition was not significantly distinguishable from the other conditions. Clothing microclimate temperature and humidity when the subjects responded thermal comfort was $28\~34^{\circ}C$ and $15\~40\%$RH without any significant difference according to age and gender. For the thermal sensation, the 24C condition was regarded as the warmest environment by the four groups, and the next preference was the 19CUW condition (p<0.001). Young females and old males showed a tendency to feel colder than young males and old females. For the thermal sensation of hands and feet, the young groups felt the warmest in the 24C condition and the coolest in the 19 C condition (p<0.001). However, old males felt neutral for the foot thermal sensation without any significant difference between the three conditions. Old females felt neutral for both the hands and feet thermal sensations without any significant difference between the three conditions. Thermal preference was the highest in the 24C condition for the 4 groups. In the 19CUW condition, for the thermal preference, most young males and females responded 'No change'; on the other hand, mea of the old responded 'Warmer'(p<0.001). It was the 24C condition that the 4 subject groups felt the most thermally comfortable. In the 19CUW condition, over $80\%$ of responses of each group expressed satisfaction and in the 19C condition, over $80\%$ of responses of each group, except young females, expressed satisfaction. In conclusion, in view of the clothing microclimate and subjective sensations, the 24C condition was the condition that gave subjects the least cold stress and the best subjective preference. However, the 19C condition and the 19CUW condition was not such a cold stress as to give healthy subjects a thermal burden.

• The Journal of Korean Physical Therapy
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• v.21 no.3
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• pp.61-68
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• 2009

Purpose: The purpose of this study was to analyze the changes of the relative impulse of the foot when carrying 5 types of schoolbag during level walking. Methods: Forty-four normal subjects were divided into 5 groups according to the method of carrying a bag: carrying no bag (condition 1), a backpack (condition 2), a shoulder bag (condition 3), a cross bag (condition 4) and a one-hand bag (condition 5). To evaluate the partial relative impulse, 7 areas were measured on the sole of a foot: the hallux, toe, 1st metatarsal head (Met1) and the 2nd & 3rd metatarsal heads (Met2/3), the 4th & 5th metatarsal heads (Met4/5), mid foot and heel. Repeated one-way analysis of variance (ANOVA) and independent t-tests were used to analyze the statistical data. Results: In the right foot, the relative impulses in every areas revealed no significant difference (p>0.05), however, the relative impulses at Met1, Met2/3, Met4/5 and heel were significantly different between the different conditions (p<0.05). There were significant differences on comparing the relative impulse between left and right foot within one condition, the mid foot in condition 2, as well as the hallux and Met1 in condition 3 (p<0.05). In condition 4, the toe, Met1, Met4/5 and mid foot were significantly different (p<0.05). The values at the hallux, toe and Met1 in condition 5 also were significantly different (p<0.05). Conclusion: These findings showed that the symmetrical relative impulse of the foot was present in the case of carrying a backpack, but there was an extra load on specific regions and asymmetrical relative impulses in the case of carrying a shoulder bag, a across bag and a one-hand bag. (ED note: this abstract is not clear. You need to work on it.)