• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2003.09a
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• pp.256-259
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• 2003

This paper presents mutual authentication scheme between user and network on mobile communications using public key scheme based on counter, and simultaneously shows key agreement between user and user using random number for secure communications. This is also a range of possible solutions to authentication and key agreement problem-authentication and key agreement protocol based on nonce and count, and secure end-to-end protocol based on the function Y=f(.)$\^$1/, C$\^$i/ is count of user I, and f(.) is one way function.

• Journal of the Korean Applied Science and Technology
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• v.38 no.3
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• pp.669-679
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• 2021

This is a quasi-experimental study using the design before and after time gap of non-equivalence with comparative group performed to confirm the effects of END smoking cessation motivational program on the Carbon monoxide, Smoking Abstinence Self-efficiency, Days of smoking, Amount of smoking in the smoking high school students. The study subjects were the smoking students in a general high school located in C-City who were interested in the smoking cessation including 27 students in test group and 28 in the control group. Data collection period was from July 12 to October 4, 2018. END smoking cessation motivational program, the test intervention in this study, The study results are as follows. "There will be a difference of physiological factors between the test group that participates in END smoking cessation motivational program and the control group that does not" is supported. smoking cessation self-efficiency(z=110.00, p<.001), Days of smoking (z=640.00, p<.001), Daily smoking amount (z=520.50, p<.016), Considering these results, the application of this program is suggested to lower the smoking rate of the smoking high school students and to motivate the smoking cessation at the schools.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.11a
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• pp.91-91
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• 2004

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.643-646
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• 2005

In this paper, we present a service model which serves multimedia contents to end consumer(End-user) that have various mobile communication terminals under a communication & broadcasting converged environment that broadcasting and communication networks are linked. A main feature of this service model is that it has a distribution structure that deliver to end consumer via adaptation of content from production of contents offering End to End (E2E) media QoS and personalized contents consumption. The proposed service model may be used as a reference model for distribution of multimedia content in communication & broadcasting converged environment in the future.

• Journal of the Korea Safety Management & Science
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• v.19 no.3
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• pp.89-95
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• 2017

This paper presents another maintenance policy for a group of units under finite operating horizon. A group of identical units are subject to random failures. Group maintenances are performed to all units together at specified intervals, and the failed units during operation are remained idle until the next group maintenance set-up. Unlike the traditional assumption of infinite operating horizon, we adopt the assumption of the finite operating horizon which reflect the rapid industrial advance and short life cycle of modern times. The units are under operation until the end of the operating horizon. Further, the operation of units are extended to the first group maintenance time after the end of the horizon. The total cost under the proposed maintenance policy is derived. The optimal group maintenance interval and the expected number of group maintenances during the horizon are found. It is shown that the proposed policy is better than the classical group maintenance policy in terms of total cost over the operating horizon. Numerical examples are presented for illustrations.

• Korean Journal of Veterinary Research
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• v.42 no.2
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• pp.277-282
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• 2002

This study was conducted to investigate the influences of the rope and the tipping chute restraints on body temperature (BT) and heart rate (HR) as acute response for stress caused by restraining for diagnasis and treatment in cattle. Both parameters were recorded by active biotelemetry. In addition cortisol concentration in blood was analyzed as a indicator for stress response. Twelve cattle were divided into two groups based on hydraulic power, the rope restraint group and the tipping chute restraint group. BT and HR were measured at -30 (base), 0, 10, 20, 30, 40, 50, 60, 90, 120, and 180 minutes, including restraint period from 0 to 30 minutes during the experiment. The results obtained in this study was summarized as follows: 1. BT of the rope restraint group was increased ($39.8{\pm}0.3^{\circ}C$) until 20 min after restraint stress for 30 min, and then maintained with high values to the end of experiment. In the tipping chute restraint group, the BT was increased ($39.6{\pm}0.3^{\circ}C$) until the end of the restraint period, but then showed decrese until the end of experiment. 2. HR of both groups was maximized at the beginning of the restraint stress (P<0.05), and then it was decreased gradually but in the tipping chute restraint group showed increase again at the end of the reatraint stress (P<0.05). 3. The cortisol level of the rope restraint group was increased significantly ($9.72{\pm}5.09{\mu}g/d{\ell}$) until 30 min after the end of the restraint stress (P<0.05) and then decreased, but in the tipping chute restraint group showed great increase ($4.68{\pm}1.56{\mu}g/d{\ell}$) at the end of the restraint stress (P<0.05) and then decreased while the tipping chute restraint group was significantly lower than the rope restraint group 30 min after the restraint stress (P<0.05). In conclusion, this study suggests that the tipping chute restraint produces less response to physical stress than the rope restraint but the time for diagnasis and treatment should be shortened when using the tipping chute restraint.

• Bulletin of the Korean Chemical Society
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• v.35 no.9
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• pp.2694-2698
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• 2014

A multisegmented polystyrene (PS) with pH-cleavable ester and carbamate linkages was successfully synthesized by a combination of atom transfer radical polymerization (ATRP) and Cu(I)-catalyzed 1,3-dipolar cycloaddition of azide and alkynes (click chemistry). ATRP was employed to synthesize polystyrene from hydroxyl-terminated initiator using CuBr/N,N,N',N",N"-pentamethyldiethylenetriamine (PMDETA) as the catalyst. The reaction of the resulting PS with sodium azide yielded the azido-terminated polymer. The hydroxyl group in the other end of the polymer was reacted with 4-nitrophenyl chloroformate (NPC), followed by reaction with propargylamine to produce an alkyne end group with a carbamate linkage. The PS with an alkyne group in one end and an azide group in the other end was then self-coupled in the presence of CuBr/2,2'-bipyridyl (bpy) in DMF to yield a desired multisegmented PS. Molecular weight and molecular weight distribution of the self-coupled polymer increased with time, as in the typical step-growth-type polymerization processes. Finally, we demonstrated that the ester and carbamate linkages of the multisegmented PS were hydrolyzed in the presence of HCl to yield individual PS chains.

• Korean Journal of Veterinary Research
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• v.54 no.1
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• pp.27-30
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• 2014

The jejunum is the longest part of the small intestine and its lumen is mainly involved in the absorption of the nutrients. The present study was conducted to evaluate the effects of metronidazole, ceftriaxoine sodium and their combination on the stenotic index of the end to end jujunal anastomotic site. To accomplish this, 20 healthy stray dogs were subjected to end to end jejunal ansastmosis. Dogs in Group A (control) underwent jejunal anstomosis with no antibiotic prophylaxis, while those in Group B received surgery and metronidazole alone at 50 mg/kg, those in Group C received ceftriaxone sodium intravenously at 30 mg/kg body weight prior to surgery and dogs in Group D were given metronidazole in combination with ceftriaxone sodium at 50 mg/kg and 30 mg/kg, respectively, 2 h before surgical intervention. No significant difference (p > 0.05) in the stenotic index was observed at 14 days after jejunal anastomosis. These findings indicate that prophylactic administration of metronidazole and ceftriaxone sodium alone or in combination had no significant effect on the stenotic index of the jejunum.

• Journal of Hospice and Palliative Care
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• v.24 no.3
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• pp.154-164
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• 2021

Purpose: The purpose of this study was to examine the effects of a death preparation education program for nurses working in convalescent hospitals on death anxiety, death attitudes, and attitudes toward end-of-life care. Methods: This was a quasi-experimental study with a non-equivalent control group, pre-test and post-test design. Among 53 participants, 26 were assigned to the non-equivalent experimental group and 27 to the control group. The program was performed in the formats of lectures, video-watching, group discussions, and sharing, and consisted of 10 sessions held twice a week, for 5 weeks (90 minutes per session). Data were analyzed using descriptive statistics, the t-test, and the chisquare test in SPSS version 21.0. Results: Significant differences between the experimental and control groups were observed in death anxiety (t=7.62, P<0.001), death attitudes (t=-7.58, P<0.001), and attitudes to end-of-life care (t=-10.30, P<0.001). Conclusion: It was confirmed that the death preparation education program reduced death anxiety and had a positive effect on death attitudes and attitudes toward end-of-life care. Based on the results of this study, it is expected that specialized and systematic education that can increase the implementation and stability of death preparation education in various fields, including nursing, will have a positive effect on both hospice patients and members of society more broadly.

• Journal of the Korean Geotechnical Society
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• v.35 no.6
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• pp.27-38
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• 2019

Bearing capacity of a pile in homogeneous soil is the sum of end bearing and skin resistance, and the skin resistance is more prominent in sandy soil. Bearing capacity of a pile in pile groups especially in sandy ground should be designed under the consideration of the influence by the adjacent piles. In this study, the end bearing capacity of a pile in pile groups was experimentally investigated. For this purpose, piles were installed in sandy ground in a circular test box, and end bearing - settlement behavior of the pile was measured while the pile was loaded. As the results, end bearing - settlement relation curves of the piles showed a distinct limit value. Limit value of the end bearing was little affected by skin friction and pile diameter, and it became a constant value as pile penetrates deeper. End bearing was not affected by the adjacent piles in a group of piles, when their clearance was larger than the pile diameter.