• Earthquakes and Structures
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• v.8 no.6
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• pp.1481-1497
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• 2015

Vertical earthquake ground motion may magnify vertical dynamic responses of structures, and thus cause serious damage to bridges. As main support structures, piers and bearings play an important role in vertical seismic response analysis of girder bridges. In this study, the pier and bearing are simplified as a vertical series spring system without mass. Then, based on the assumption of small displacement, the equation of motion governing the simply-supported straight girder bridge under vertical ground motion is established including effects of vertical deformation of support structures. Considering boundary conditions, the differential quadrature method (DQM) is applied to discretize the above equation of motion into a MDOF (multi-degree-of-freedom) system. Then seismic responses of this MDOF system are calculated by a step-by-step integration method. Effects of support structures on vertical dynamic responses of girder bridges are studied under different vertical strong earthquake motions. Results indicate that support structures may remarkably increase or decrease vertical seismic responses of girder bridges. So it is of great importance to consider effects of support structures in structural seismic design of girder bridges in near-fault region. Finally, optimization of support structures to resist vertical strong earthquake motions is discussed.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.22 no.10
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• pp.687-696
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• 2010

In this study, FDD algorithm was developed using the normalized distance method and general pattern classifier method that can be applied to constant air volume air handling unit(CAV AHU) system. The simulation model using TRNSYS and EES was developed in order to obtain characteristic data of CAV AHU system under the normal and the faulty operation. Sensitivity analysis of fault detection was carried out with respect to fault progress. When differential pressure of mixed air filter increased by more than about 105 pascal, FDD algorithm was able to detect the fault. The return air temperature is very important measurement parameter controlling cooling capacity. Therefore, it is important to detect measurement error of the return air temperature. Measurement error of the return air temperature sensor can be detected at below $1.2^{\circ}C$ by FDD algorithm. FDD algorithm developed in this study was found to indicate each failure modes accurately.

• Korean Management Science Review
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• v.21 no.2
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• pp.123-143
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• 2004

Internet shoppers interact with Internet shopping mall systems while they shop. To understand why Internet shoppers make purchase, this study view Internet shopping malls as information systems. Although this view point seems reasonable, little previous studies employing this perspective are found in the relevant literature. This study develops a research model where Internet shoppers' transaction intentions are affected by the mediating effects of trust and satisfaction. Trust can mitigate uncertainty of the e-commerce environment for consumers, and satisfaction is widely used to measure the effectiveness of information systems. Therefore, we consider them as key elements in this study. We further employ the construct of website quality to explain why shoppers have different levels of trust and satisfaction. We classify website quality into information quality, system quality. and design quality. We collected 282 survey responses from Internet shoppers who have prior experiences with Internet shopping malls to purchase a product or service. The survey data are used to empirically test the proposed nine research hypotheses using LISREL. The LISREL results indicate that information quality and design quality have significant impact on both satisfaction and trust, while system quality has little relation to trust level. Further, trust is shown to have significant influence on satisfaction. Finally. both trust and satisfaction is strongly related to the future transaction intention.

• Journal of the Korean Society for information Management
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• v.28 no.3
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• pp.219-238
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• 2011

The purpose of this study is to examine the causal relationships among knowledge management system(KMS) quality, perceived ease of use, perceived usefulness, attitude, and continuance use of KMS. The results of data analysis by structured equation model(SEM) indicate that KMS quality significantly influences individual's perceived ease of use and perceived usefulness. Perceived ease of use affects individual's perceived usefulness on KMS. Individual's perceived ease of use and perceived usefulness affect on the creation of a positive attitude, and attitude affects continuance use of KMS. Based on the results, theoretical and practical implications of this study are discussed.

• Advances in Traditional Medicine
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• v.4 no.4
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• pp.249-252
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• 2004

The methanol extract of Diospyros peregrina bark was studied for its effect on the central nervous system (CNS) using the pentobarbitone induced sleeping time test, the open field test and the hole cross test in Swiss albino mice. The present investigation revealed that the extract, at the doses of 250 and 500 mg/kg, significantly prolonged the pentobarbitone induced sleeping time in mice though the onset of sleep was delayed as compared to the control. In open field test, the depressing effect was prominent from the second observation period (30 min) and persisted throughout the entire experimental period (240 min). In the hole cross test, the depressing effect was observed from the second observation period (30 min) and persisted up to fifth observation period (120 min) for 250 mg dose group and up to sixth observation period (180 min) for 500 mg dose group. These results support the finding that D. peregrina bark extract at the above doses has CNS depressing effects and indicate that D. peregrina bark may contain biologically active constituent(s) having CNS depressant activity.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.46 no.4
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• pp.76-81
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• 2009

We propose an effective emotion recognition algorithm based on the minimum classification error (MCE) incorporating multi-modal system The emotion recognition is performed based on a Gaussian mixture model (GMM) based on MCE method employing on log-likelihood. In particular, the reposed technique is based on the fusion of feature vectors based on voice signal and galvanic skin response (GSR) from the body sensor. The experimental results indicate that performance of the proposal approach based on MCE incorporating the multi-modal system outperforms the conventional approach.

• The KSFM Journal of Fluid Machinery
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• v.19 no.4
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• pp.19-28
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• 2016

Objective of this study is to compare the inherent characteristics of natural convection flow inside the canister of spent fuel dry storage system with different backfill gases by utilizing computational fluid dynamics (CFD) code. Four working fluids were selected for comparison study. Helium currently used backfill gas for canister, air, nitrogen, and argon are frequently used as coolant in many heat transfer applications. The results indicate that helium has very distinct conductive behavior and show very weak natural convective flow compared to the others. Argon showed the strongest natural convective flow but also the worst coolability. Air and nitrogen showed similar characteristics to each other. However, due to difference in Prandtl number, nitrogen showed more effective natural convective flow. These results suggest that experimental validation for the nitrogen is needed to investigate the potential coolability other than currently commercially used helium.

• Journal of electromagnetic engineering and science
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• v.11 no.1
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• pp.34-41
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• 2011

This paper proposes a systematic design for a precoding codebook for a transmit-ing space-division multiple access (TN-SDMA) sharing spectrum with existing fixed wireless service (FWS). Based on an estimated direction angle of a victim FWS system, an interfering transmitter adaptively constructs a codebook, forming a transmit in the direction angle, while satisfying orthogonal beamforming constraints. Sum throughput results indicate that the throughput loss of TN-SDMA relative to a practical SDMA, called per user unitary and rate control ($PU^2RC$), is lower at larger number of transmission antennas, lower signal-to-noise ratio, or a smaller number of users. In particular, a small loss (12% throughput loss) is provided for practical system parameters. Spectrum sharing results confirm that TNSDMA efficiently shares spectrum with FWS systems by reducing protection distance to more than 66 %. Although a TN-SDMA system always has lower throughput compared to $PU^2RC$ in non-coexistence scenarios; it offers an intriguing opportunity to re-use a spectrum already allocated to an FWS.

• Journal of Korean Academy of Nursing
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• v.24 no.2
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• pp.216-225
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• 1994

The cost of hospice care should be covered by the insurance system if it is to be promoted in our country and this, in turn, requires a proper method to the estimate of this cost. The purpose of this study was to set up the method to estimate the cost of hospice care. First the cost effectiveness of hospice care were studied. By tracing the activities of hospice nurses for a given period, all the relevant data such as the scope and load of activities as well as the cost were collected. Then these were analysed and compared with the data obtained from hospice and home care. The results showed that the cost of hospice care was the most economic, and indicate its qualification as .1n in-dependent system. The main part of the cost of hospice care was found to be the labor cost which was up to 83% of the total. Therefore a method to estimate the cost should reflect the real labor cost. Several methods have been proposed in the study in terms of unit labor cost, service time, material cost, and the weight of the labor cost. All variables, including the service time surveyed in this study, can easily be translated into numerical values and it would not difficult to estmate the cost of hospice care. Hence by letting the hospice care be insured, hospice care can be expected to function as a good alternative to the present medical system.

• Journal of Radiation Protection and Research
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• v.41 no.3
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• pp.301-309
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• 2016

Background: A contamination screening process for the local population in radiation emergencies is discussed. Materials and Methods: We present an overview of the relevant Korean governmental regulations that underpin the development of an effective response system. Moreover, case studies of foreign countries responding to mass casualties are presented, and indicate that responses should be able to handle a large demand for contamination screening of the local public as well as screening of the immediate victims of the incident. Results and Discussion: We propose operating procedures for an off-site contamination screening post operated by the local government for members of the public who have not been directly harmed in the accident. In order to devise screening categories, sorting strategies assessing contamination and exposure are discussed, as well as a psychological response system. Conclusion: This study will lead to the effective operation of contamination screening clinics if an accident occurs. Furthermore, the role of contamination screening clinics in the overall context of the radiation emergency treatment system should be clearly established.