• Macromolecular Research
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• v.17 no.12
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• pp.1003-1009
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• 2009

Copolymers of N-vinylpyrrolidone (NVP) comonomer with styrene (St), hydroxypropyl methacrylate (HPMA) and carboxyphenyl maleimide (CPMI) were synthesized by free radical polymerization using 2,2'-azobisisobutyronitrile (AIBN) initiator in 1,4-dioxane solvent. The copolymers formed were characterized by FTIR, $^1H$ NMR and $^{13}C$ NMR techniques and their thermal properties were studied by DSC and TGA. Copolymer composition was determined by $^1H$ NMR and/or by elemental analysis and monomer reactivity ratios (MRR) were estimated by the linear methods of Kelen-Tudos (K-T) and extended Kelen-Tudos (EK-T) and the non-linear approach. Copolymers of St and HPMA with NVP formed blocks of one of the monomer units, whereas alternating copolymers were obtained in CPMI-NVP, depending upon the side chain substitution. The MRR values are discussed in terms of monomer structural properties such as electronegativity and electron delocalization. The sequence distribution of monomers in the copolymers was studied by statistical method based on the average reactivity ratios obtained by EK-T method.

• Child Health Nursing Research
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• v.10 no.3
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• pp.350-360
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• 2004

Purpose: To suggest ideas that promote sexual health and useful in planning sex education programs for middle school students. Method: This study surveyed 661 middle school students from three schools in Seoul and Chunchon. Result: The average degree of sexual knowledge was 31.5, while attitude was 32.5. There were statistically significant differences in sexual knowledge in relation to: coeducational environment (t=-5.776, p=.000), grade (F=36.351, p=.000), father's age (t=-2.510, p=.012), mother's age (t=-2.146, p=.032), economical status (F=3.264, p=.039), source of sexual knowledge (F=8.484, p=.000), the degree of interest in the opposite sex (F=16.871, p=.000), sexual discussions with parents (t=3.556, p=.000), sexual discussions with teachers (t=2.847, p=.005), and sex education (t=2.148, p=.032). Likewise, stastically significant differences in sexual attitudes were linked to: coeducational environment (t=-7.646, p=.000), subject's grade (F=32.743, p=.000), parental marriage status (t=2.338, p=.020), mother's age (t=-2.048, p=.041), source of sexual knowledge (F=6.917, p=.000), the degree of interest in the opposite sex (F=15.559, p=.000), sexual discussions with parents (t=3.908, p=.000), and sexual discussions with teachers (t=2.946, p=.003). The students level of sexual knowledge and attitude was significantly correlated (r=.686, p=.000). Conclusion: This study indicates a variety of systematic sexual education programs are needed for middle school student at home and school.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.05a
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• pp.82-84
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• 2022

In recent years, research has been actively conducted to solve overhead problems caused by the increase in the number of IoT devices. MQTT, one of the IoT lightweight protocols for resolving performance degradation in IoT environments, is standardized to enable efficient operation in many-to-many communication environments, but there is a security vulnerability as it does not provide encryption by default. Although TLS communication technology can be applied to solve these problems, it is difficult to meet IoT's lightweight power-saving requirements. This paper introduces the latest MQTT communication encryption trends and analyzes IoT applicability by comparing TLS encryption and payload encryption methods.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.4D
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• pp.459-465
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• 2009

u-T (ubiquitous transportation) environment can be envisioned as an advanced version of ITS environment and be expected to provide more advanced transportation service in a ubiquitous manner. As a basic necessity to measure traffic flow in both environments, a flow estimation method was proposed. Flows have been measured in existing ITS and in a new u-T environments and some differences were investigated using simulation technique. In the interrupted traffic situation, the flow rate of u-T is 3.58% higher than that in ITS environment. Both MARE and MAE, which were used as measure of effectiveness, in u-T were better since the results are 31.4% and 31.1% lower than in ITS, respectively. Besides the equality coefficient in u-T was 1.9% higher than that in ITS. Such being the case, the flow rate measured in u-T using U-TSN is more reliable and can be expected to be successfully used for transportation system design or traffic operation areas.

• Journal of Internet of Things and Convergence
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• v.6 no.2
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• pp.45-50
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• 2020

In this paper, we propose a QoS-based handover management scheme in SDN. Even though there have been lots of recent services such as IoT, the conventional networks provide a monolitic handover method without considerations on flow-specific QoS features. For example, the conventional Internet provides a handover method which only considers IP continuity. On the other hand, 4G and 5G networks use a strict handover method for all kinds of flows with resource reservations. This means that it is difficult to guarantee the QoS requirements for the flow with a strict QoS requirement in Internet and the inefficient resource utilization can occur in the 4G and 5G because of the strict QoS-based handover management. The proposed scheme proposes the flow handover management scheme based on QoS requirements according to the SDN controller's management. From the network operators' perspective, the proposed scheme can provide the efficient resource utilization as well as QoS provisioning.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.1475-1476
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• 2010

• Proceedings of the Korean Vacuum Society Conference
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• 2004.08a
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• pp.79-79
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• 2004

• Computational Structural Engineering
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• v.24 no.3
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• pp.8-18
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• 2011

• Journal of the Korean Magnetics Society
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• v.3 no.2
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• pp.139-142
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• 1993

The Rabi's NMR experiment using polarized flowing water was performed in order to measure the low field and the good NMR signal was obtained in the range of 0.1 mT. There was a change in amplitude and phase of signal due to the sinusoidal variation with the increasing RF field. The nominal field could be determined within a few tens ppm uncertainty by the NMR signal under the optimized RF condition.

• Child Health Nursing Research
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• v.9 no.4
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• pp.359-367
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• 2003

Purpose: This study is designed to test the effects of a full body massage on Apgar score, postpartum mother's childbirth experience, and mother-infant attachment for primipara during labor. Method: Data were collected using a quasi-experiment method (nonequivalent control group, pre-post test design) from November 1, 2001 to July 31, 2002. The subjects for this experiment consist of 28 women in the experimental group and 29 in the control group, out of 57 primipara hospitalized at the U OB & GYN hospital in Inchon. A 20 minute full body massage was given to the experimental group on each of three delivery phases (latent, active, and transition), and a conventional delivery care to the control group. The experimental tools for the study are Apgar score scale developed by Apgar(1958), postpartum mother's childbirth experience scale developed by Marut and Mercer(1979), and mother-infant attachment scale developed by Cropley et al(1981). The data collected were analyzed using t-test, χ2 test, and ANCOVA on the SPSS program. Result: The results of the experiment are as follows: One minute(t=6.756, p=.000; F=9.181, p=.004), and five minute(t=6.129, p=.000; F=7.918, p=.007) Apgar score are increased significantly. Postpartum mother's childbirth experience is significantly increased(t=11.691, p=.000; F=11.741, p=.001). Verbal touch score(t=5.256, p=.000; F=7.169, p=.010), skin touch score(t=11.332, p=.000; F=27.073, p=.000), and total score(t=12.105, p=.000; F=30.104, p=.000) of postpartum mother's childbirth experience are significantly increased, but not for eye touch score(t=3.236, p=.002; F=.800, p=.375). Conclusion: This study shows that a full body massage has a significant positive effect on Apgar score, postpartum mother's childbirth experience. and mother-infant attachment. Therefore, it is suggested that the full body massage might be used clinically to help primipara during labor.