• The KIPS Transactions:PartA
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• v.13A no.4 s.101
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• pp.351-362
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• 2006

This paper proposes an adaptive inter-agent communication protocol to considerably reduce the amount of agent location information maintained by each service node and the message delivery time while avoiding the dependency of the home node of a mobile agent. To satisfy this goal, the protocol enables each mobile agent to autonomously leave its location information only on some few of its visiting nodes. Also, it may significantly reduce the agent cache updating frequency of each service node by keeping the identifier of the location manager of each agent in the smart agent location cache of the node. Simulation results show that the proposed protocol reduces about $76%{\sim}80%$ of message delivery overhead and about $76%{\sim}79%$ of the amount of agent location information each service node should maintain compared with the traditional one.

• The Korean Nurse
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• v.36 no.3
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• pp.70-80
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• 1997

This study of elderly in-patient subjects' expected level of care given by family members and nurses is intended to provide foundational information for use by nurses is attending to elderly patients. The objects of the study were elderly in-patients over the age of 65 hospitalized at two General hospitals in Chonju: 102 subjects filled out the 60 question survey between December 16 and 24. 1996. The analysis process was conducted using SPSS producing percentage. mean and standard deviation. maximum and minimum values. t-test, ANOVA. and so on. The results are as follows: 1. From the general results of the survey. one can observe that statistically significant differences appeared in various levels of education of the subjects: no education(2.98). primary school completed(2.91). middle school or higher completed(2.77). As shown. the lower level of education correlates with higher care-giving expectation. 2. On a scale of 1(minimum) to 4(maximum). the mean levels of care expected by elderly inpatients from their families is 2.93. with a standard deviation of 0.28. The level of psychological care expected(mean 3.02. standard deviation 0.31) is higher than the level of care expected(mean 2.83. standard deviation 0.34). 3. The level of care expected among those of different levels of dependency for daily living (differentiated as dependent. partially dependent. independent) was highest among the partially dependent(mean 2.98. standard deviation 0.17). but the results were not statistically significant. 4. Elderly in-patients with high levels of emotive interaction with their families expected relatively high levels of physical care. while the highest levels of socio-psychological care were expected from those who reported normal levels of emotive interaction with their families. However. We can see that low levels of care are expected from those reporting low levels of emotive interaction with their families. Overall. the differences in the level of care expected between those reporting different levels of emotive interaction with their families was not shown to be statistically significant.

• Applied Chemistry for Engineering
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• v.30 no.3
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• pp.345-351
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• 2019

In this study, the hollow fibers from $TiO_2$ and various metal oxides additives were fabricated and characterized in order to remove the arsenic substance from a contaminated water. Experimental results showed the best arsenic adsorption performance from pristine $TiO_2$ hollow fibers. When metal oxides were added, the metal oxides reduced the acid sites on the surface of $TiO_2$ and the arsenic adsorption performance decreased. However, the long term arsenic adsorption performance was enhanced and showed better performance than that of using pristine $TiO_2$ hollow fibers when $Al_2O_3$ was added during the hollow fiber fabrication. In addition, the arsenic adsorption performance showed a high dependency on the specific surface area of hollow fibers. It was confirmed that the abundancy of Lewis and Bronsted acid sites provided was favorable for the arsenic adsorption. It was also demonstrated that commercially available $TiO_2$ powders can be an attractive candidate material for manufacturing hollow fibers for a small scale water treatment plant.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.49 no.1
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• pp.41-52
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• 2021

During atmospheric ascent of a launch vehicle, airborne acoustic loads act on the vehicle and its effect becomes pronounced at transonic speed. In the present study, acoustic loads acting on a hammerhead launch vehicle at a transonic speed have been analyzed using ��-ω SST based IDDES and the results including mean Cp, Cprms, and PSD are compared to available wind-tunnel test data. Mesh dependency of IDDES results has been investigated and it has been concluded that with an appropriate turbulence scale-resolving computational mesh, the characteristic flow features around a transonic hammerhead launch vehicle such as separated shear flow at fairing shoulder and its reattachment on rear body as well as large pressure fluctuation in the region of separated flow behind the boat-tail can be predicted with reasonable accuracy for engineering purposes.

• Wind and Structures
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• v.35 no.1
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• pp.21-34
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• 2022

Gust factor is an important parameter for the conversion between peak gust wind and mean wind speed used for the structural design and wind-related hazard mitigation. The gust factor of typhoon wind is observed to show a significant dispersion and some differences with large-scale weather systems, e.g., monsoons and extratropical cyclones. In this study, insitu measurement data captured by 13 meteorological towers during a strong typhoon Morakot are collected to investigate the statistical characteristics, height and wind speed dependency of the gust factor. Onshore off-sea and off-land winds are comparatively studied, respectively to characterize the underlying terrain effects on the gust factor. The theoretical method of peak factor based on Gaussian assumption is then introduced to compare the gust factor profiles observed in this study and given in some building codes and standards. The results show that the probability distributions of gust factor for both off-sea winds and off-land winds can be well described using the generalized extreme value (GEV) distribution model. Compared with the off-land winds, the off-sea gust factors are relatively smaller, and the probability distribution is more leptokurtic with longer tails. With the increase of height, especially for off-sea winds, the probability distributions of gust factor are more peaked and right-tailed. The scatters of gust factor decrease with the mean wind speed and height. AS/NZ's suggestions are nearly parallel with the measured gust factor profiles below 80m, while the fitting curve of off-sea data below 120m is more similar to AIJ, ASCE and EU.

• Journal of Climate Change Research
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• v.34 no.12
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• pp.5081-5092
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• 2021

Paleoproxy records indicate that abrupt changes in thermohaline circulation (THC) were induced by rapid meltwater discharge from retreating ice sheets. Such abrupt changes in the THC have been understood as a hysteresis behavior of a nonlinear system. Previous studies, however, primarily focused on a near-static hysteresis under fixed or slowly varying freshwater forcing (FWF), reflecting the equilibrated response of the THC. This study aims to improve the current understanding of transient THC responses under rapidly varying forcing and their dependency on forcing time scales. The results simulated by an Earth system model suggest that the bifurcation is delayed as the forcing time scale is shorter, causing the Atlantic meridional overturning circulation collapse and recovery to occur at higher and lower FWF values, respectively. The delayed shutdown/recovery occurs because bifurcation is determined not by the FWF value at the time but by the total amount of freshwater remaining over the THC convection region. The remaining freshwater amount is primarily determined by the forcing accumulation (i.e., time-integrated FWF), which is modulated by the freshwater/salt advection by ocean circulations and freshwater flux by the atmospheric hydrological cycle. In general, the latter is overwhelmed by the former. When the forced freshwater amount is the same, the modulation effect is stronger under slowly varying forcing because more time is provided for the feedback processes.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.24 no.2
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• pp.49-56
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• 2018

A novel printable time-temperature integrator (TTI) composed of a natural coloring matter, anthocyanidin, was developed. The anthocyanin was biochemically modified to change in color over week scale, compared to the original anthocyanin over month scale change. The anthocyanin extracted from strawberry was converted to its aglycone, anthocyanidin, by the treatment with ${\beta}-glucosidase$. The print paste was composed of the freeze-dried powder of anthocyanidin, pullulan, glycerol and distilled water, which was screen-printed. The TTI performance were examined in terms of kinetics and temperature dependency. The activation energy of anthocyanidin TTI was 86.92 kJ/mol. Compared with the activation energy of foods, the applicable food groups were found. Applicable food groups were chilled meat products and fish. The major benefits of the TTI were the printability to be practical in use and the eco-friendliness with the natural pigment.

• The Journal of the Acoustical Society of Korea
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• v.22 no.8
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• pp.652-659
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• 2003

High-frequency(40∼120 kHz) reflection loss measurements on the water-sandy sediment with a flat interface were conducted in a water tank for various grazing angles. The water tank(5×5×5 m) was filled with a 0.5 m-thick-flat bottom of 0.5ø-mean-grain-size sand. Reflection losses, which were experimentally obtained as a function of grazing angle and frequency, were compared with the forward loss model, APL-UW model (Mourad & Jackson, 1989). For frequencies below 60 kHz, the observed losses well agree with the reflection loss model, however, in cases for frequencies above 70 kHz, the observed losses are greater by 2∼3 dB than the model results. The model calculation, which does not fully account for the vertical scale of roughness due to grain size, produce less bottom losses compared to the observations that correspond to large roughness based on the Rayleigh parameter in the wave scattering theory. In conclusion, for the same grain-size-sediment, as frequencies increase, the grainsize becomes the scale of roughness that could be very large for the frequencies above 70 kHz. Therefore, although the sea bottom was flat, we have to consider the frequency dependence of an effect of roughness within confidential interval of grain size distribution in reflection loss model.

• Journal of Korean Physical Therapy Science
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• v.4 no.2
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• pp.439-452
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• 1997

Mothers of handicapped children experience many problems and difficulties related to the child's prolonged dependency and demands for special care. Social support can be identified as stress-relieving factor, social support is considered to decrease the amount of negativeness in an individual or family. This study attempted to identify the level of burden and social support in mothers of children who are handicapped, and to determine whether social support is an effective strategy for burden relief in these mothers. The method used in the study was a correlational descriptive survey using a questionnaire. The subjects for the study were 42 mothers who have the handicapped children, between two to twelve years of age, being treated at S General Welfare House for Handicapped and S Rehabilitation Center in Seoul. The data were collected during 1 month from March 20 to April 20, 1996. The instruments used for this study was a structured questionnaire which was the Burden scale developed by Suh Mihae and Oh Kasil(1993) and the PRQ(Personal Resource Questionnaire) scale developed by Brandt & Weinert(1981). The collected data were analyzed using the SPSS computer program, yielding frequencies, percentiles, means, standard deviations, $x^{2}$-test, Pearson's correlation coefficienct, t-test and ANOVA. The results of this study are as follows ; 1)The range of age in the subjects was $29{\sim}44$ years, the range age in the handicapped children was $2{\sim}12$ years. 2) The mean score of burden, for the mothers of the handicapped children was 2.75(standard deviation was 0.47) of a possible total of 5. 3) The mean score of social support, for the mothers of the handicapped children was 4.99 (standard deviation was 0.59) of a possible total of 7. 4) There was an negative correlations hip between burden level and the social support, but there was no statistically significant correlationship between burden level and the social support(r = -.2252, p = .076) 5) In the general characteristics influencing on the burden level was significantly related with the sex(t = - 2.87, p = .007) and the degree of child's handicap level(F = 11.8680, p = .000l). In the general characteristics influencing on the social support was significantly related with the family(husband) support(F = 3.5199, p = .0240). There were significant differences in the mother's levels of burden depending upon the severity of child's handicap. In other words, the degree of mother's burden was directly proportionate to the degree of child's handicap level. There were significant differences in the mother's levels of social support depending upon the family(husband) support. In conclusion, on the basis of the results of this study, there was no statistically significant correlationship between burden level and the social support. Above results suggest that strategies for the intervention programs in diminishing the mother's burden and reinforcing the social support.

• Journal of the Korean Society for Marine Environment & Energy
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• v.15 no.2
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• pp.142-149
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• 2012

This study deals with the investigation of the scale effect for the vertical-axis tidal stream turbine by evaluating the hydrodynamic efficiency of turbine rotors of different diameters at different flow conditions. Numerical analyses are made for the turbine rotors with a same shape, but different sizes obtained using the diameter evaluation equation suggested in this paper. It is shown that the performance of turbine is clearly dependent upon the rotor size and inflow velocity, i.e. Reynolds number dependency of different-scaled turbines showing better efficiency with increasing Reynolds number. The sudden decrease of efficiency is also noticed around the transition region of Reynolds number. The hydrodynamic capacity evaluation method needed at initial stage of turbine design is suggested and exercised with some test cases. It is recommended that the method is expected to be useful for turbines with demanding powers between 10 kW and 300 kW.