• Earthquakes and Structures
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• v.10 no.2
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• pp.463-482
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• 2016

Air Traffic Control (ATC) towers play significant role in the functionality of each airport. In spite of having complex dynamic behavior and major role in mitigating post-earthquake problems, less attention has been paid to the seismic performance of these structures. Herein, seismic response of an existing ATC tower with a wall-frame structural system that has been designed and detailed according to a local building code was evaluated through the framework of performance-based seismic design. Results of this study indicated that the linear static and dynamic analyses used for the design of this tower were incapable of providing a safety margin for the required seismic performance levels especially when the tower was subjected to strong ground motions. It was concluded that, for seismic design of ATC towers practice engineers should refer to a more sophisticated seismic design approach (e.g., performance-based seismic design) which accounts for inelastic behavior of structural components in order to comply with the higher seismic performance objectives of ATC towers.

• Korean Journal of Occupational Health Nursing
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• v.21 no.3
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• pp.283-289
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• 2012

Purpose: The purpose of this study was to identify the effects of the social support and ego-resilience on the nursing performance among hospital nurses. Methods: The subjects of this study were 369 nurses in a senior general hospital. We used the self-reported questionnaire to assess the level of ego-resilience, social support and nursing performance of hospital nurses. The data were analyzed using descriptive statistics, frequency, t-test, ANOVA, Pearson's correlation coefficient and stepwise multiple regression. Results: This study showed the positive relationship between the social support and ego-resilience on tne the nursing performance of hospital nurses. The higher group of the social support and ego-resilience showed the more performance of hospital nurses. And, the influencing factors on the performance are age, ego-resilience, social support, night working days a month in the order. Conclusion: Further studies will be needed to promote the performance of nurse in hospital and policies to be develop to elevate the social support and ego-resilience of nurses.

• Journal of the Ergonomics Society of Korea
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• v.29 no.4
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• pp.605-610
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• 2010

In order to design a touch interface for the elderly, human performance of input tasks on the touch screen was investigated by the laboratory experiment. Input times and input errors were measured in the experimental conditions that were changed according to age, key size, interkey space and input tool(finger or stylus pen). In the most of all experimental conditions, the task performance of the elderly was lower than that of the young. However, there were significantly different performance patterns between both groups. As the difficulty of task was getting higher, the task performance of the elderly was sharply decreased; pressing small key button by finger sharply increased input time and error rate, compared to that of the young. Therefore, the square key size suitable to the elderly may be over $8.0{\times}8.0mm$. While the interkey space did not influence to the input task performance of the young, the task performance of the elderly was influenced. The elderly showed big difference of task performance according to input tool. However, the young were less influenced by input tool.

• Journal of the Korea Society for Simulation
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• v.28 no.1
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• pp.1-9
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• 2019

Recently, as the importance of warehouses has increased, much efforts are being made to improve the picking process in order to cope with a small amount of high frequency and fast delivery. This study proposes an algorithm to assign orders to pickers in the situation where Single Order Picking policy is used. This algorithm utilizes five attributes related to picking such as picking processing time, elapsed time after receipt of order, inspection/packing workstation situation, picker error, customer importance. A measure of urgency is introduced so that the units of measure for each attribute are the same. The higher the urgency, the higher the allocation priority. In the proposed algorithm, the allocation policy can be flexibly adjusted according to the operational goal of the picking system by changing the weight of each attribute. Simulation experiments were performed on a hypothetical small logistics warehouse. The results showed excellent performance in terms of system throughput and flow time.

• Journal of the Korean Society of Food Culture
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• v.21 no.5
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• pp.524-535
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• 2006

The purpose of this study was to identify the differences of cognitive responses, emotional responses, customer satisfaction, and service loyalty about service encounter quality by types of restaurants and to analyse emotional responses, customer satisfaction, and service loyalty in accordance with level of service encounter quality. The questionnaire were collected from customers (N=812) who had used restaurants in Seoul, aiming at 15 or more-year-old customers from October 24, 2005 to November 6, 2005. The main results of this study were as follows: Statistically significant difference was showed in importance and performance of interaction quality, importance and performance of physical environment quality, performance of outcome quality depending on types of restaurants, while significant difference was not indicated in importance of outcome quality by types of restaurants. Positive emotional response was significantly high by types of restaurants in order of fine-dining restaurants, family restaurants, and fast-food restaurants, while negative emotional responses were significantly higher in fast-food restaurants than in the other two types. As far as Customer satisfaction are concerned, fine-dining restaurants showed higher customer satisfaction than the other two types. Attitudinal service loyalty was high in fine-dining restaurants, family restaurants and fast-food restaurants in order and behavioral loyalty was not significantly different with each type of restaurant. In accordance with level of service encounter quality, cluster analysis was conducted and the clusters were divided into 'high-valuation' and 'low-valuation'. 'High-valuation cluster' and 'low-valuation cluster' showed significant difference depending on types of restaurants that customers used(p<.001). The customers who used fine-dining restaurants and family restaurants valued the performance of service encounter highly. However, in fast-food restaurants, a lot of low-valuation customers existed. Therefore, fast-food restaurants have to improve performance of interaction quality, outcome quality and physical environment quality in service encounter. In addition, in 'high-valuation cluster' who valued service encounter quality highly showed higher scores in positive responses, customer satisfaction, service loyalty than in 'low-valuation cluster', and showed low negative responses.

• Korean Journal of Child Studies
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• v.2
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• pp.1-16
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• 1981

This study had two purposes. First, to examine the stages and developmental order of object permanence based on Piaget's theory. Second, to assess the effects of delay, attentiveness, and direction of gaze. Two experiments were conducted to examine the object permanence development in infants. The subjects for the 2 experiments were randomly drawn from a well-baby clinic. The subjects for Experiment 1 were 72 infants, 12 each in 6 age levels : 6, 9, 12, 15, 18, and 21 months old. Experiment 1 was designed to examine the stages and developmental order of object concept development, ana infants received 5 tasks as follows : (1) finding an object partially hidden under one box (2) finding an object completely hidden under one box (3) finding an object after successive visible displacements (4) finding an object after one invisible displacement (5) finding an object after successive invisible displacements. The subjects for Experiment 2 were 24 9-month-olds. Experiment 2 was designed to assess the effects of delay, attentiveness, and direction of gaze for Stage IV of object concept development. Subjects were equally assigned into one of two delay groups: 0-sec delay and 3-sec delay. Attentiveness was rated in terms of a three-point scale, and then divided into high and low attentive groups. Direction of gaze was judged into two directions. In two experiments, infants received three trials of task, and received a score of 0, 1, 2 for each trials. Data were analyzed by ANOVA, Tukey test, and t-test for task performance, and direction of gaze was analyzed by chi-square. The results obtained from two experiments were as follows : 1. In object permanence test, subjects obtained significantly higher scores with age, and 6, 9, 12, 18 months were classified into different developmental stages. 2. In object permanence development, subjects received significantly different scores with task and a developmental order of tasks was found. First of all, infants mastered finding an object partially hidden under one box, and then mastered finding an object completely hidden under one box. Contrary to Piagetian theory, in this study, the development of finding an object after successive visible displacements and finding an object after one invisible displacement were sometimes reversed. Finally, finding an object after successive invisible displacements was mastered, and the concept of object permanence was completed. 3. In Stage IV of object concept development, a 3-sec delay did not significantly affect the performance of tasks. The O-sec delay group didn't perform significantly better than the 3-sec delay group. 4. In Stage IV of object concept development, attentiveness of infants significantly affected the performance of task. So the highly attentive infants obtained better performance scores than the low attentive infants. 5. In Stage IV of object concept development, direction of gaze significantly affected the performance of task. That is, infants who gazed at the box which contained the object showed a higher rate of success than infants who gazed at the box which had already displaced the object.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.13 no.4
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• pp.1-7
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• 2017

The energy slab is a ground coupled heat exchanger equipped in building slab structures, which represents a layout similar to the horizontal ground heat exchanger (GHEX). The energy slab is installed as one component of the floor slab layers in order to utilize the underground structure as a hybrid energy structure. However, as the energy slab is horizontally arranged, its thermal performance is inevitably less than the conventional vertical GHEXs. Therefore, stainless steel (STS) pipes are alternatively considered as a heat exchanger instead of high density polyethylene (HDPE) pipes in order to enhance thermal performance of GHEXs. Moreover, not only a floor slab but also a wall slab can be utilized as a heat-exchangeable energy slab in order to maximize the use of underground space effectively. In this paper, four field-scale energy slabs were constructed in a test bed, which consist of the STS and HDPE pipe, and a series of thermal response tests (TRTs) was conducted to evaluate relative heat exchange efficiency per unit pipe length according to the pipe material and the configuration of energy slabs. The energy slab equipped with the STS pipe shows higher thermal performance than the energy slab with the HDPE pipe. In addition, thermal performance of the wall-type energy slab is almost equivalent to the floor-type energy slab.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.7
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• pp.1511-1517
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• 2014

Based on the simulation model for phase noise effect, the phase noise performance of communication system using the M-ary APSK modulation method is analyzed in this paper. The phase noise effects for APSK higher order modulation method are modeled by considering the signal constellations of the modulation methods. The simulation model is verified by comparing the analytic results for lower order modulation signals with simulated results for those modulation signals. Based on the simulation model, then, the phase noise effects for M-ary APSK are analyzed. The simulated results for PSK lower order modulation signals are in agreement with the results by the analytic model in the order of 1 %. The proper phase noise effects for M-ary APSK modulation signals are deduced by the simulation model. Also, the required signal-to-noise ratios of phase noise are proposed for phase noise degradations, which are used as the design parameter that considers the phase noise effect.

• Proceedings of the KIEE Conference
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• 1997.07f
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• pp.1961-1963
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• 1997

A new higher reaching speed algorithm for the position control systems of the treveling wave type Ultrasonic Motors(USM) is presented. As the frictional forces of the stator materials revolves the rotor, the temperature of the contact surfaces is increased. It deteriorates the performance of control system so that the control frequency of inverter deviate from the natural resonant frequence of USM during the normal operation. In order to get higher reaching speed in the position control, we propose a novel algorithm that detect the resonant frequency of USM using the simple hardware and decision Processing. The effectiveness of proposed algorithm is verified by the experimental results.

• The Journal of Asian Finance, Economics and Business
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• v.7 no.4
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• pp.163-171
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• 2020

The study aims to examine the effects of inward every presence of foreign investment, import, and real exchange rate shocks on export performance in Vietnam. This study employs a time-series sample dataset in the period of 2009 - 2018. All data are collected from the General Statistics Office of Ministry of Planning and Investment in Vietnam, World Development Indicator and Ministry of Finance, State Bank of Vietnam. This study employs the Augmented Dickey-Fuller test and the vector error correction model with the analysis of cointegration. The results demonstrate that a higher value of import significantly accelerates export performance in the short run, but insignificantly generates in the long run. When the volume of registered foreign investment goes up, the export performance will predominantly decrease in the both short run and long run. Historically, countries worldwide are more likely to devaluate their currencies in order to support export performance. According to the study, the exchange rate volatility has an effect on the external trade in the long run but no effect in the short run. Finally, Vietnam's export performance converges on its long-run equilibrium by roughly 6.3% with the speed adjustment via a combination of import, every presence of foreign investment, and real exchange rate fluctuations.