• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.10
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• pp.2028-2037
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• 2009

This paper presents the simulator for dynamic modeling of a MT(micro turbine) during start-up period. The simulator is implemented by modeling a dynamic power of main components of a MT including compressor, combustor and turbine. A modeling for a MT under steady state operation can be accurately built from thermodynamics analysis. But dynamic modeling during start-up period is very difficult because efficiency of main components is very low and the designed value has big error and nonlinear characteristics during start-up. In this paper, new method without using thermodynamics analysis during start-up is proposed for the simulator. The power models of main components are derived from analysis of the experimental operation data by test motoring using a electric starter under constant power output. The simulator is developed using MATLAB/Simulink. For constant power output control, sensorless vector inverter is designed and algorithms for starting from stall and method for controling a output power are proposed. The performance of developed simulator is verified by comparing experimental and simulation start-up results.

• Industrial Engineering and Management Systems
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• v.12 no.2
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• pp.95-102
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• 2013

It is difficult to determine an appropriate discount price for daily perishable products to increase profit from a long-term standpoint. Even if the discount pricing is efficient to increase profit of the day, consumers memorize the sales price and they might hesitate to purchase the product at a regular price the following day. The authors discussed the inventory clearance pricing for a single period in our previous study by constructing a mathematical model to derive an optimal sales price to maximize the expected profit by considering the reference price effect of demand. This paper extends the discussion to handle the discount pricing for multiple periods. A mathematical analysis is first conducted to reveal the properties on an objective function, which is the present value of total expected profits for multiple periods. An algorithm is then proposed to derive an optimal price for asymmetric consumers. Numerical experiments investigate the characteristics of the objective function and optimal pricings.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.7
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• pp.34-40
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• 2014

In this paper, we want to know the optimal replacement cycle(time) for this study was performed. The optimal preventive replacement age can be fond by finding the value of time that minimizes the cost function(model of Barlow and Jardine). In addition, The reliability of the relay according to the service environment were studied. The use of the exchange relay period is longer, and maintenance cost rate(per hour) may increase, and also the reliability may cause a decline. In addition, considering the preventive maintenance and purchase order, a representative relay(RAX-L440-A type) life was calculated.

• Korea journal of population studies
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• v.17 no.2
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• pp.1-20
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• 1994

The main purpose of this paper is to examine changes in internal migration patterns during 1960 - 1990 period, and to analyze population movement to and from the Capital Region. The overall mobility rate of the whole Korean population has heen increasing since the 1960s, and reached to 24.6% in 1985 - 90 period. The most interesting changes in the migration pattern is that Seoul lost its population through migration during 1985 - 90, mainly due to heavy outmigration to Kyonggi province. The analysis of characteristics of inmigrants to the Capital Region reveals that those moved to Seoul are more likely to be young, better educated, never married and engage in service sector in comparison with migrants moved to the suburban districts and the outlying Kyonggi province. However, on the whole migrants moved to the Capital Region are overrepresented in manufacturing sector, which suggests that more effective policy measures to control the growth of manufacturing sector in the Capital Region is called for.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.38 no.5 s.118
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• pp.66-73
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• 2006

The effects of active packaging on the surface stiffness, mass, volume, density and weight changes of fresh as well as stored eggplant were studied at 11 and $25^{\circ}C$ for 10 days with active packaging material Type 1 and 2 and control. Mass, volume, and surface stiffness of eggplant decreased linearly throughout the storage period regardless of storage conditions; while the mass density showed a reverse trend in the ease of $11^{\circ}C$ storage. Reduction rate of mass, mass density and weight was observed minimum at $25^{\circ}C$ storage temperature with active packaging Type 1. The weight of eggplant decreased at a higher rate in the initial 4 days compared to that in the later period of storage regardless of storage temperature and type of packaging.

• International Journal of Computer Science & Network Security
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• v.21 no.2
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• pp.40-43
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• 2021

In the article of instability on the peak power level, duration and repetition period of a multifrequency space-time signal, we calculated the maximum values of the errors of the parameters of the laws of spatial-phase-frequency control. Requirements for the accuracy of the location of the phase centers of the emitters in a cylindrical phased array antenna with pyramidal horns; it is advisable to calculate the radiation field using single-stage and multi-stage distribution laws. The phase centers of individual radiation sources of a cylindrical phased array antenna have been studied; they have almost no effect on the duration and period of recurrence.

• International Journal of High-Rise Buildings
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• v.11 no.2
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• pp.137-144
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• 2022

As one of the most important vertical transportation equipment in super high-rise buildings, the construction elevator directly affects the project period, cost, and effectiveness. The paper proposes a new construction elevator with single-guide rail and multi-cages. It can solve the problems of single construction elevator capacity shortage and efficacy decrease with height reduction, the occupancy of plan and elevation position of multiple construction elevators, and extension of total construction period by cycling operation of multi-cages on a single-guide rail. The paper focuses on the design and research of the main components of the equipment, such as the rotating guide rail mechanism, vertical bearing mast tie system, segmented electrical power supply system, group control scheduling system, and safety anti-collision system.

• Journal of the East Asian Society of Dietary Life
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• v.21 no.1
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• pp.74-81
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• 2011

This study was carried out to investigate the effect of red wine on the color, hardness, springiness, chewiness, pH, volatile basic nitrogen (VBN) content, thiobarbituric acid reactive substances (TBARS) value, and total bacterial number of pork meat stored at $4^{\circ}C$ for 10 days. Pork meat was treated with 25% water (control), 20% water and 5% red wine (RW5), 15% water and 10% red wine (RW10), or 10% water and 15% red wine (RW15). The lightness ($L^*$), redness ($a^*$) and yellowness ($b^*$) values tended to decrease with longer storage period (p<0.05). The $L^*$ values of RW10 and RW15 were higher than those of control and RW5 on the first day of storage, whereas the control and RW5 had higher $L^*$ values compared to RW10 and RW15 after 10 days (p<0.05). Hardness of RW5 was the lowest after 10 days of storage (p<0.05). The pH levels were not significantly different among the samples. The VBN contents increased with longer storage period (p<0.05), and those of RW10 and RW15 were lower than those of the control and RW5 after 10 days of storage (p<0.05). The TBARS values increased with longer storage period (p<0.05), and those of the control, RW5, RW10, and RW15 were 0.61, 0.45, 0.35 and 0.33 mg MA/kg, respectively, after 10 days of the storage. The total bacterial numbers increased with longer storage period, and those of RW5, RW10 and RW15 were lower compared to the control (p<0.05). Taste, tenderness, juiciness, and palatability were not significantly different among the samples, but the flavor of RW5 had the highest value after 10 days of storage (p<0.05). These results suggest that red wine can inhibit protein degradation, lipid oxidation, and bacterial growth when used as an additive of seasoned pork meat.

• The Journal of Korean society of community based occupational therapy
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• v.4 no.1
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• pp.75-84
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• 2014

Objective : This study intends to suggest an effective clinical intervention method for stroke patients by applying a trunk stabilization training program to a single stroke patient and investigating and analyzing the effects of the program on postural control and activities of daily living. Methods : The subject of this study was a 75 year-old female stroke patient hospitalized in C Hospital located in Gyeongju, Gyeongsangbuk-do. As for the research design, A-B-A reversal design was used with a single subject design; and the research period was a total of five weeks from April 21, 2014 to May 23, 2014. As for the research process, a total of 15 sessions were carried out including three sessions of baseline(A), nine sessions of an intervention period(B), and three sessions of maintenance(A'); and the trunk stabilization program was applied during the intervention period. To evaluate the participant's postural control and activities of living life, the Postural Assessment Scale for Stroke(PASS) and the modified Barthel Index(MBI) were used. Visual analysis was used in which collected data were plotted on a graph, using Microsoft Office Excel 2013. Results : In the postural control test, the mean scores improved from 11.7 in the baseline phase to 14.8 in the intervention phase and 15.3 in the maintenance phase. In the evaluation of activities of daily living, the score improved from 66(medium dependence) during the baseline period to 80(low dependence) after intervention and at the maintenance phase. Conclusion : It was found that the trunk stabilization training program showed effects on the stroke patient's postural control or alignment, and furthermore a beneficial improvement in the patient's performing the activities of daily living, as well.

• Journal of Korean Public Health Nursing
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• v.9 no.1
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• pp.44-58
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• 1995

This study was to investigated the relationship between health locus of control and health promoting behavior of College students. For this study, questionnaires were given to 300 students in the H University of Seoul and collected during the period from Nomber 17 to November 24, 1994. Health locus of control and health promoting behavior were measured by using the MHLC scale and a modified HPLP scale. Healthiness of life style is parameterized by self actualization, health responsibility, exercise, nutrition, stress management, and internal support. The data were analyzed using the statistics package SAS, yielding frequency, percentage, mean, standard deviation, t-test, ANOVA, Pearson's Correlation. The result of this analysis are as follows: 1. Among the components of health locus of control, internal health locus of control showed the highestscore (mean: 3. 12, standard deviation: 0.46). Powerful others health locus of control followed next with the mean of 2. 30 and the standard deviation of 0.44. Chance health locus of control showed the mean of 2.29, and the standard deviation of 0.43 2. The HPLP mean score and the standard deviation of practice of health promoting behavior were 2.51 and 0.31 respectively. 3. HPLP correlated positively with internal health locus of control (r= 0.20, p<.01) and powerful others locus of control (r= 0.21. p<.001). However, HPLP inversely correlated with chance locus of control (r=-0.13, p<.05) 4. The demographic variables representing sex (t= 2.26, p<.05), health status (F = 5.52, p<.01) showed connections to health promoting behavior. Therefore, nurses should consider health locus of control when they take care of College students to improve such health promoting behavior as self actualization, exercise, internal support, stress management, and health responsibility. Further research is required to discover factors influencing health promoting behavior of College students.