• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.4A
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• pp.677-687
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• 2006

Kriging interpolation is one of the generally used interpolation techniques in Geostatistics field. This technique includes the experimental and theoretical variograms and the formulation of kriging interpolation. In contrast to the conventional least square method for stress recovery, kriging interpolation is based on the weighted least square method to obtain the estimated exact solution from the stress data at the Gauss points. The weight factor is determined by variogram modeling for interpolation of stress data apart from the conventional interpolation methods that use an equal weight factor. In addition to this, the p-level is increased non-uniformly or selectively through a posteriori error estimation based on SPR (superconvergent patch recovery) technique, proposed by Zienkiewicz and Zhu, by auto mesh p-refinement. The cut-out plate problem under tension has been tested to validate this approach. It also provides validity of kriging interpolation through comparing to existing least square method.

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.77-80
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• 1999

This paper deals with a design of a symbol timing recovery circuit of QAM using the interpolation in AWGN channel. To reduce timing jitter and the amount of processing data, we employ MGA (Modified Gardner Algorithm) as a symbol timing error detector which is called NDA(Nondecision Directed Algorithm). We show the characteristics (S-curve and the variance) of timing error detector with the roll-off factor of a shaping filter, which are compared with GA. Also, we compare the BER curve of interpolation method with that of ideal case. The performance of the STR is shown to be close to that of ideal case. This result shows that this method can be useful to implement symbol timing recovery circuit for multi-level modulation.

• Proceedings of the SAREK Conference
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• 2005.11a
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• pp.294-299
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• 2005

In order to control indoor air quality and save energy. it is needed to install a suitable ventilation system equipped with heat exchanger for heat recovery. Paper heat exchanger can recover $50{\sim}70$ of the enthalpy difference between supply and exhaust air. The purpose of this research is to obtain the experimental correlations for the friction factor, heat transfer coefficient, mass transfer coefficient and permeance of paper heat exchanger, which can be used for the performance prediction of the paper heat exchanger. Pressure drop at various velocities and heat transfer rate at various dry-bulb temperatures, relative humidities, and specific humidities are measured to make experimental correlations. The results of prediction using correlations show fairly good agreement with experimental data.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.54 no.11
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• pp.540-547
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• 2005

One of the roles of AGC is to regulate the frequency of power systems. AGC is also used to control the frequency of Korean Power System. AGC control strategies depend on system characteristics and the requirements of the systems to which those are applied. Korean Power System consists of one control area and does not have tie-lines. In this research, an AGC control strategy is suggested to avoid conflict with governor dynamics and to enhance frequency recovery It shows good performance for regulation and frequency recovery. This control strategy is expected to be applied to New EMS in KPX to get reasonable AGC regulation and frequency recovery performance.

• International Area Studies Review
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• v.15 no.2
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• pp.225-245
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• 2011

This study investigates the effects of justice dimensions on negative emotion, consumer satisfaction after service recovery, repurchase intention and word-of-mouth intention in a context of service recovery. Behavioral intentions(repurchase intention and word-of-mouth intention) are critical to the discount store sellers' survival and success. The research model is an extension of previous studies, especially considering more recent developments in the service recovery literature. A survey using 458 customers in China was conducted, confirmatory factor analysis was conducted to test the validity of the measurement model, and AMOS analysis approach was used to gain important insights into how customer retention in the discount store business can be ensured. The results suggest that all three dimensions of justice had negative effects on negative emotion, had positive effects on satisfaction after service recovery. Negative emotion had negative effects on recovery satisfaction. Recovery satisfaction had positive effects on repurchase intention and word-of-mouth intention. Finally, this study suggests the implications of these findings and offers directions for future research.

• Archives of Plastic Surgery
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• v.48 no.1
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• pp.26-32
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• 2021

Background Although loss of sensation in patients with breast cancer after mastectomy followed by breast reconstruction is an important factor affecting patients' quality of life, the mechanism of sensory recovery is still unclear. Our study aimed to identify variables that affect sensory recovery, especially pain, in reconstructed breasts. Methods All patients with breast cancer who underwent mastectomy followed by immediate breast reconstruction, including nipple reconstruction or areolar tattooing, were included in this study. Sensation was evaluated in the nipple as an endpoint of sensation recovery of the whole breast. Patients rated pain severity using a 3-point verbal rating scale (VRS): grade 0, no pain; grade 1, mild to moderate pain; and grade 2, severe pain. The VRS was assessed by a single experienced plastic surgeon. Results In the univariate analysis, the odds ratio (OR) for sensation recovery was 0.951 for age (P=0.014), 0.803 for body mass index (P=0.001), 0.996 for breast volume before surgery (P=0.001), 0.998 for specimen weight after mastectomy (P=0.040), and 1.066 for the period between mastectomy and sensory assessment (P=0.003). In the multivariate analysis, the variables that showed a significant effect were age (OR, 0.953; P=0.034), the period between mastectomy and sensory assessment (OR, 1.071; P=0.006), and reconstruction using abdominal tissue instead of prosthetic reconstruction (OR, 0.270; P=0.004). Conclusions Based on our results, it can be inferred that aging has a negative impact on the recovery of sensation, breast sensation improves with time after surgery, and the recovery of sensation is better in prosthetic reconstruction.

• Journal of Energy Engineering
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• v.24 no.4
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• pp.1-10
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• 2015

For successful operation of waterflooding which is one of secondary recovery methods, suitable water injection allocation is important to increase oil recovery. Well allocation factor(WAF) which is one way to quantify the injector and producer connectivity, is utilized to allocate water injection of waterflooding. Static WAF cannot represent the field condition and can induce incorrect value. To compensate for limitation of static WAF, modified WAF which includes several parameters that affect patterns including well radius, distance between wells, and injection rates is proposed. In this study, static and modified WAFs were applied to injection optimization of waterflooding and results by each WAF were compared. In case of modified WAFs, produced water were less and produced oil were more than case of static WAF especially in big change of distance between producer and injector. Therefore, modified WAFs can allocate water injection more efficiently than static WAF.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.4
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• pp.537-545
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• 2013

The elastic recovery of a metal seal is a factor that can be used to assess its sealing performance. In this study, a compliant mechanism topology optimization has been performed to find a structure of a metal O-ring seal that can maintain excellent sealing performance with a maximized elastic recovery over extended operation. An evolutionary structural optimization (ESO) was used as a topology optimization algorithm with two different types of objective functions considering both flexibility and stiffness. In particular, a circular design domain was adopted to consider the outer shape of the metal O-ring seal. The elastic recovery of the optimal topology was calculated and compared to that of a commercial product.

• The Journal of Korean Medicine
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• v.30 no.3
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• pp.28-38
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• 2009

Background : Peripheral nerve injuries are a commonly encountered clinical problem and often result in a chronic pain and severe functional deficits. Objective : The aim of this study was to evaluate the effects of Gentianae Macrophyllae Radix (G. M. Radix) on the pain control and the recovery of the locomotor function that results from the sciatic crushed nerve injury in rats. Method : Using rats, we crushed their sciatic nerve, and then orally administered the aqueous extract of G. M. Radix. The effects of G. M. Radix on the recovery locomotor function were investigated by walking track analysis. The effects of G. M. Radix on pain control were investigated by brain-derived neurotrophic factor (BDNF) expression in the sciatic nerve, and c-Fos expression in the paraventricular nucleus (PVN) of the hypothalamus and in the ventrolateral periaqueductal gray (vlPAG). Result : G. M. RADIX facilitates motor function from the locomotor deficit, and thereby increased BDNF expression and suppressed painful stimuli in the PVN and vlPAG after sciatic crushed nerve injury. Conclusion : It is suggested that G. M. Radix might aid recovery locomotor function and control pain after sciatic crushed nerve injury. Further studies on identifying specific the component in G.M. Radix associated with enhanced neural activity in the peripheral nerve injury may be helpful to develop therapeutic strategies for the treatment of peripheral nerve injury.

• Transactions of the Korean Society of Automotive Engineers
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• v.17 no.4
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• pp.101-107
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• 2009

Actuators using shape memory alloys use the one-way shape recovery stress. But when external load is applied the accumulated plastic strain induced by repeated deformation is the factor of generation of uncorrect recovery stress and unreliability. To solve this problem, two-way shape memory effect (TWSME) is considered. TWSME induced by plastic deformation have advantages including simple heating cycle without external force and enough recovery force for using actuators. but there is no research on cylinder-type or tube-type shape memory alloy actuators using two-way shape memory effect until now. Therefore in this study, characteristics of two-way shape memory effect is verified through the compression experiments using cylinder-type and tube-type specimens.