• Journal of the Korean Society for Precision Engineering
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• v.18 no.2
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• pp.90-95
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• 2001

f-$\theta$len is one of the important parts in Laser Scanning Unit because it affects on the optical performance of Laser Scanning Unit dominantly. It is necessary to find out the relationship between the surface profile error of f-$\theta$lens and the beam profile focusing on the Organic Photo Conductive drum in order to analysis the beam profile problems such as appearance of side lobe and expansion of center lobe. In this research, a simulation process which relates the surface profile characteristics to the beam profile has been developed by CODE V. The simulated beam profile also have been compared with the measurement results.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.1
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• pp.74-76
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• 2008

• The Korean Journal of Nuclear Medicine
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• v.32 no.6
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• pp.542-544
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• 1998

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.11a
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• pp.139-139
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• 2004

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.5
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• pp.121-133
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• 2013

Defect-free transfer service on the Next-generation wireless network extensive roaming mobile node (MN) to provide efficient mobility management has become very important. MIPv6(Mobility IPv6) is one of mobility management scheme proposed by IETF(Internet Engineering Task Force), and IPv6-based mobility management techniques have been developed in various forms. One of each management techniques, IPv6-based mobility management techniques for PMIPv6 (MIPv6) system to improve the performance of a variety of F-PMIPv6 (Fast Handover for Proxy MIPv6) is proposed. However, the F-PMIPv6 is cannot be excellent than PMIPv6 in all scenarios. Therefor, to select a proper mobility management scheme between PMIPv6 and F-PMIPv6 becomes an interesting issue, for its potenrials in enhancing the capacity and scalability of the system. In this paper, we develop an analytical model to analyze the applicability of PMIPv6 and F-PMIPv6. Based on this model, we design an Secure Smart Mobility Support(SSM) scheme that selects the better alternative between PMIPv6 and F-PMIPv6 for a user according to its changing mobility and service characteristics. When F-PMIPv6 is adopted, SSM chooses the best mobility anchor point and regional size to optimize the system performance. Numerical results illustrate the impact of some key parameters on the applicability of PMIPv6 and F-PMIPv6. Finally, SSM has proven even better result than PMIPv6 and F-PMIPv6.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.7
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• pp.54-65
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• 2020

This randomized pre-post-controlled experimental study determined the effect on patients' anxiety, stress, systolic blood pressure, heart rate and Bis index when the Healing Beats program is applied after epidural blockage. The subjects were selected from the patients who visited the Department of Anesthesiology and Pain for the treatment of epidural blockage and volunteered through the recruitment announcement. A total of 74 sets of data were collected and analyzed with 25 subjects in the experimental group, 24 in the placebo group, and 25 in the control group. The data was analyzed using descriptive statistics, x2-tests, F-tests and repeated measures of ANOVA. As a result of the study, the general characteristics and variables of the experimental group, placebo group, and control group were all the same, and anxiety was measured twice before and after the study. There were significant differences between groups (F=27.175, p<.001), and stress (F=4.78, p<.001), heart rate (F=4.22, p<.001) and the Bis index (F=7.96, p<.001) were analyzed by variance according to population and time. There was a significant difference. However, there was no significant difference in systolic blood pressure (F=1.23, p=.298). In conclusion, the Healing Beats program can be used as an effective and effective intervention for sedation in clinical situations or stressful situations.

• Journal of the military operations research society of Korea
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• v.34 no.2
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• pp.163-174
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• 2008

The military is an organization where reliability and availability take much more importance than in any other organization. And, in line with a recent trend of putting emphasis on 'system readiness', not only functions but also availability of a weapon system has become one of achievement targets. In this regard, the military keeps spares for important facility and equipment, which is called as Maintenance Float (M/F), in order to enhance reliability and availability in case of an unforeseen event. The military has calculated yearly M/F requirements based on the number of equipment and utilization rate. However, this method of calculation has failed to meet the intended targets of reliability and availability due to lack of consideration on the characteristics of equipment malfunctions and maintenance unit's capability. In this research, we present an analysis model that can be used to determine an optimal M/F inventory level based on queuing and absorbed Markov chain theories. And, we applied the new analysis model to come out with an optimal volume of K-1 tank M/F for the OO division, which serves as counterattack military unit. In our view, this research is valuable because, while using more tractable methodology compared to previous research, we present a new analysis model that can describe decision making process on M/F level more satisfactorily.

• Fire Science and Engineering
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• v.26 no.4
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• pp.24-30
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• 2012

The purpose of this study is to analyze the problem in measuring the differential pressure between the fire area and the neighboring smoke control zone as well as the opening force of a fire door and to present the actual values measured by an objective method. NFSC 501A specifies that the force necessary to open an access door when operating a smoke control system shall be less than 110 N. When the smoke control system does not operate in the space where it is installed, the door opening force can be measured by the test method in KS F 2805. However, when the smoke control system operates, additional opening force is required to overcome the force generated by the differential pressure between the fire area and smoke control room. Therefore, it can be seen that the method proposed by the standard has insufficient reliability. The analog measuring device and digital measuring device showed that the opening forces, $F_a$ and $F_d$, of the fully closed door before the smoke control system were 27.8 N and 27.4 N, respectively. When the door remained open by $5^{\circ}$, the opening forces, $F_a$ and $F_d$, were 33 N and 33.6 N, respectively. When the smoke control system operated and the door was fully closed, the door opening forces, $F_a$ and $F_d$, were 77.6 N and 76.0 N, respectively. Therefore, since the door opening forces are different from the criteria presented by KS F 2805, it is required to review the criteria appropriately.

• Journal of Astronomy and Space Sciences
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• v.26 no.4
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• pp.499-510
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• 2009

In this paper, relative orbit of Low Earth Orbit satellites is determined using only GPS measurements and the effects of Equatorial Spread-F (ESF), that is one of biggest ionospheric irregularities, are investigated. First, relative orbit determiation process is constructed based on doubly differenced GPS observations. In order to see orbit determination performance, relative orbit of two GRACE satellites is estimated for one month in 2004 when no ESF is observed. The root mean square of the achieved baselines compared with that from K-Band Ranger sensor is about 2~3 mm and average of 95% of ambiguities are resolved. Based on this performance, the relative orbit is estimated for two weeks of two difference years, 2003 when there are lots of ESF occurred, and 2004 when only few ESF occurred. For 2003, the averaged baseline error over two weeks is about 15 mm. That is about 4 times larger than the case of 2004 (3.6 mm). Ionospheric status achieved from K-Band Ranging sensor also shows that more Equatorial Spread-F occurred at 2003 than 2004. Investigation on raw observations and screening process revealed that the ionospheric irregualarities caused by Equatorial Spread-F gave significant effects on GPS signal like signal loss or enhancement ionospheric error, From this study, relative orbit determination using GPS observations should consider the effect of Equatorial Spread-F and adjust orbit determination strategy, especially at the time of solar maximum.

• Korean Journal of Environment and Ecology
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• v.29 no.6
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• pp.858-864
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• 2015

Developmental changes in the vocal signals of serotine bats (Eptesicus serotinus) during their infancy were examined in this study. The analysis was conducted on 4 infant serotine bats from 1 to 40 days after their birth. Pulse duration (PD), pulse interval (PI), peak frequency (PF), maximum frequency ($F_{MAX}$), minimum frequency ($F_{MIN}$), and bandwidth (BW) were measured. As the bats grew, their vocalizations became increasingly consistent and similar to those of adults. For infant bats, PD and PI decreased as they grew older, whereas PF, $F_{MAX}$, $F_{MIN}$, and BW increased. The greatest change in vocalizations was observed between the $10^{th}$ and $20^{th}$ days after birth. Also, PF, $F_{MAX}$, $F_{MIN}$ and BW, which describe sound frequency, increased dramatically during the period between the $10^{th}$ and the $20^{th}$ days. In contrast, the greatest change in PD occurred between the $30^{th}$ and $40^{th}$ days after birth. The results collected in this study suggest that frequency increased as the contraction ability of the muscles developed by around 20 days of age. Muscle relaxation ability, which is related to PD, was found to develop significantly at 30 to 40 days of age. According to the results of this study, although 40 day-old infant bats are not yet able to fly, their vocal signals were similar to those of adults. This indicates that vocal development and flying activity develop separately in young bats.