• Journal of Navigation and Port Research
• /
• v.30 no.1 s.107
• /
• pp.97-104
• /
• 2006

Recently the first stage qf construction for Busan new port emerged over the sea surface at the north container terminal site. With this, there are lot of discussions and debates on increasing the water depth at the approaching channel and mooring basin from the existing 15m to 18m by dredging work in order to be able to serve 12,000TEU containership, and at the same time, correction to the reclamation plan of hinterland at the part of Undong Bay qf the new port site. Since the attack of typhoon 'Maemi' in 2003, it is expected that the design wave parameters for coastal and harbor structures in this area would be somewhat changed and so the extreme wave condition at each terminal and tranquility of berthing area does, and therefore, it is necessary to analyze the tranquility at each berth Hence in this study, we constructed a wave model for these conditions and performed simulation together with the circulation model simulation, compared with the field data collected The result showed the increase of the harbor response throughout the basin but not severe condition However, a certain location needs to be prepared for the rough sea condition when a severe typhoon hit the site.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2008.04a
• /
• pp.41-41
• /
• 2008

In general, polyimides (PIs) are used in alignment layers in liquid crystal displays (LCDs). The rubbing alignment technique has been widely used to align the LC molecules on the PI layer. Although this method is suitable for mass production of LCDs because of its simple process and high productivity, it has certain limitations. A rubbed PI surface includes debris left by the cloth, and the generation of electrostatic charges during the rubbing induces local defects, streaks, and a grating-like wavy surface due to nonuniform microgrooves that degrade the display resolution of computer displays and digital television. Additional washing and drying to remove the debris, and overwriting for multi-domain formation to improve the electro-optical characteristics such as the wide viewing angle, reduce the cost-effectiveness of the process. Therefore, an alternative to non-rubbing techniques without changing the LC alignment layer (i.e, PI) is proposed. The surface of LC alignment layers as a function of the ion beam (IE) energy was modified. Various pretilt angles were created on the IB-irradiated PI surfaces. After IB irradiation, the Ar ions did not change the morphology of the PI surface, indicating that the pretilt angle was not due to microgrooves. To verify the compositional behavior for the LC alignment, the chemical bonding states of the ill-irradiated PI surfaces were analyzed in detail by XPS. The chemical structure analysis showed that ability of LCs to align was due to the preferential orientation of the carbon network, which was caused by the breaking of C=O double bonds in the imide ring, parallel to the incident 18 direction. The potential of non-rubbing technology for fabricating display devices was further conformed by achieving the superior electro-optical characteristics, compared to rubbed PI.

• Journal of Navigation and Port Research
• /
• v.39 no.3
• /
• pp.149-156
• /
• 2015

The Dynamic Positioning System consists of 7 elements which are namely Power system, Human machine interface, DP Computer, Position Reference System(PRS), Sensors, Thruster system and DP Operator. Incidents like loss of position(LOP) on DP vessel usually occur due to errors in these 7 elements. The purpose of this study is to find out safety operation method of DP vessel through qualitative and quantitative analyze of DP LOP incidents which are submitted to IMCA every year. The 612 DP LOP incidents submitted from 2001 to 2010 were analyzed to find out the main cause of the incidents and its rate among other causes. Consequently, the highest rate of incidents involving DP elements are PRS errors. DP computer, Power system, Human error and thruster system came next. The PRS has been analyzed and a flowchart was drawn through expert brainstorming. Also, the conditional probability has been analyzed through Bayesian Networks based on this flowchart. Consequentially, the main causes of drive off incidents were DGPS, microwave radar and HPR. Also, this study identified the main causes of DGPS errors through Bayesian Networks. These causes are signal blocked, electric components failure, relative mode error, signal weak or fail.

• Progress in Medical Physics
• /
• v.6 no.2
• /
• pp.41-50
• /
• 1995

The absorbed dose and contaminant electron distribution of therapeutic X-ray beam (15MV photon) was studied with a half blocked beams of 30$\times$30$\textrm{cm}^2$ and field size ranging from 5$\times$5 to 30$\times$30$\textrm{cm}^2$. For a 15MV photon beam energy, the value of the depth of dose maximum, d$_{max}$, gradually decrease with increasing field size from 5$\times$5 to 30$\times$30$\textrm{cm}^2$ due to mainly by contaminant electrons which are produced in the flattening filter and scattered by collimator jaws, tray holder〔Lucite〕, blocking block and air. The results suggest that separate dosimetry data should be kept for blocked and unblocked field. The inherence of the contaminant electrons to the open field depth of maximum dose can lead to mistaken results if attenuation measurements are made at that depth. A nurmerous contaminant electrons mainly were distributed as shape of corn in the central photon beam and their path length in the water were shorter than 30mm because of the electrons energy having around 6MeV. These results clearly appears that the substraction of scattered electrons (electrons and positrons) from the total depth dose curve not only lowers the absolute dose in the bulidup region and surface dose, it also causes a shift of d$_{max}$ to a deeper depth. In the terapeutic high energy photon beam, the absorbed dose near the buildup region is the combined result of incident contaminant electrons and phantom generated electronsrons.

• Journal of Preventive Medicine and Public Health
• /
• v.28 no.2 s.50
• /
• pp.473-486
• /
• 1995

A hospital-based, matched case-control study was carried out to evaluate the relation ship of various suspected risk factors including snoring and serum level of cholesterol to cerebrovascular disease in Korea. A total of 127 incident cases of cerebrovascular disease(74 cases of cerebral infarction and 53 cases of intracerebral hemorrhage) admitted to. the department of neurology in a university hospital from December, 1993 to March, 1995 were compared with 127 matched controls admitted to same hospital in same period. A multivariate analysis suggested that ECG abnormality(left ventricular hypertrophy and atrial fibrillation), family history of cerebrovascular disease, fundoscopic abnormality, previous history of transient ischemic attack and hypercholesterolemia were risk factors of cerebrovascular disease, ECG abnormality, fundoscopic abnormality, smoking and hypercholesterolemia were also suggested as risk factors of cerebral infarction.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.11 no.4
• /
• pp.201-215
• /
• 1999

Field measurements were made for long- and short-period waves and current velocities at the harbor mouth using pressure-type wave gauges and a current meter, respectively, at the Gamcheon Harbor which has a rectangular shape with a narrow entrance. The measured pressure data were subjected to spectral analyses after removing tidal effects by applying trend removal and high-pass filtering. For the band averaging of the raw spectra, in order to obtain good resolution over the entire frequency, instead of a constant band width, variable band widths were used, which gradually increase as marching from the lowest frequency towards higher frequencies. The Helmholtz resonance mode at the Gamcheon Harbor shows the relative amplification ratio of 9.2 at the wave period of 31.7 minutes, which is quite large compared with those at the harbors located on the east coast of Korea. The second and the third resonance period was 10.3 and 5.4 minute, respectively. On the other hand, the analysis of every 24 hours data shows that during storms the spectral densities are very large compared to those during calm seas and also the second and third resonances are predominant.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.27 no.4
• /
• pp.228-237
• /
• 2015

Field observations were conducted to collect hydrodynamic and morphological data, which are needed to account for mechanisms of bathymetry changes caused by physical forcings, in Haeundae beach. In order to quantitatively describe characteristics of wave transformations and current patterns in space in winter and summer, in-situ sensors for measuring waves and current profiles were installed at three locations in the cross-shore direction and also three locations in the along-shore direction. As for the results of wave measurements, waves with main direction from the east dominate in winter while waves are incident from the S and the ESE in summer. Analysis of current data reveals that currents over the study domain are considerably influenced by a pattern of tidal motions, thereby, mainly oscillating in the direction of tidal currents, i.e., east-west directions, in both winter and summer. Currents tend to be influenced by local bathymetry in the shallow water region, with the direction changed along the depth contours and the magnitude reduced as they approach the shoreline. The results analysed from the hydrodynamic data through this study can be further combined with the morphological and bathymetry data, leading to the quantification of seasonal sediment transport rates and sand budget changes.

• Journal of Satellite, Information and Communications
• /
• v.8 no.4
• /
• pp.150-158
• /
• 2013

In Korea, the official monitoring of the atmospheric re-entry of satellites or space debris was initiated by the first operation of a re-entry situation analysis team for the 'Cosmos 1402' of the Soviet Union, which main body re-entered on January 23, 1983 and radio active core re-entered on February 7, 1983. After this incident, a task force team consisting Korea Astronomy and Space Science Institute (KASI), Korea Aerospace Research Institute (KARI) and other related institutes operated a situation monitoring group under the supervision of the Ministry of Science and technology (MOST) for the controlled re-entry of the Russian 'Mir' space station in 2001. The re-entry of the upper atmospheric weather satellite 'UARS' of United States had been monitored and analyzed by KASI on September 24, 2011. As the re-entry of the space object has been frequently occurred, the government officials and the experts from MEST (Ministry of Education, Science and Technology), KASI, KARI had an urgent official meeting to establish a satellite re-entry monitoring room in KASI and to give an operational authority to KASI in September 14, 2011. Under this decision, the satellite re-entry monitoring room in KASI has successfully executed the monitoring, data analyzing, official reporting, media contacting, and public announcing for the German satellite 'Roentgen' in October 2011, Russian space explorer 'Phobos-Grunt' in January 2012, Russian satellite 'Cosmos 1484' in January 2013, and European geodetic satellite 'GOCE' in November 2013 with the support from the Korean Air Force and KARI.

• Women's Health Nursing
• /
• v.2 no.2
• /
• pp.284-297
• /
• 1996

A maternity ward in a hospital in Seoul has an educational program for postpartal mothers since its opening, but evaluation on the program has not been done. This study was to find whether the educational program contributed to increase of knowledge and confidence of the post-partal mothers in the area of postpartal self-care and the newborn baby care or not. This study aimed at improvement of the educational program for posrpartal mothers and the newborn babies. Subjects were 40 primiparae who were admitted to the obstetric ward in a general hospitals in Seoul from August 20th to September 10th, 1995. Subjects were those who had no labor pain at the admission time, had no complications during labor and delivery, gave a birth to a healthy baby, and agreed to participate in this study. All subjects were well educated and were in well-to-do group. Most of them received antenatal care adequately. They were tested on knowledge and self-confidence in the area of postpartal self-care and infant care two times, one at the admission time and the other prior to discharge. After the first test, nurses in a maternity ward and nursery taught them on postpartal self-care and infant care. Education consisted of a 1 hour planned program and incident teachings done at bed side. Four tools were developed by authors based literature review. The test tool for knowledge of postpartal self-care consisted of 15 items which included the definition of postpartum, dangerous symptoms in postpartum, lochia, time to begin coitus, postpartum exercise, sitz-bath, and perineal care. The test tool for self-confidence in postpartal self-care included such items as emergency care on dangerous symptoms in postpartum, sexual life and contraception after postpartum, self-confidence in postpartum exercise and perineal care. The test tool for knowledge of newborn baby care consisted of 18 items which included bathing, umbilical cord care, vaccination, breast feeding, abnormal symptoms of neonate. The test tool for self confidence in the newborn baby care included umbilical cord care, vaccination, breast feeding, emergency care for baby. Analysis of demographic data were analyzed with calculation of percentage. Score differences between the first test and the second test were analyzed with paired t-test. SAS / PC (Release 6.04 for DOS) program are as follows. 1. Mothers' knowledge of postpartal self-care increased significantly after education (t=10.04, df=38, p=0.0001). 2. Mothers' self-confidence in postpartal self-care increased significantly after education (t=6.53, df=38, p=0.0001). 3. Mother's knowledge of the newborn abay care increased significantly after education (t=9.74, df=38, p=0.0001). 4. Mothers' self-confidence in the newborn baby care increased significantly after education(t=8.22, df=38, p=0.0001) Suggestions for further studies and nursing practice were as follows. 1. We suggest studies by randomized control-group pretest-posttest design or nonequivalent control group pretest-posttest design will be done. 2. We suggest follow-up studies to find if mothers's confidence will last or not after discharge. 3. We suggest general hospitals to establish a phone-counseling system.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.36 no.11B
• /
• pp.1346-1356
• /
• 2011

Transportation has been playing important role in our society by providing for people, freight, and information. However, it cuts its own throat by causing car accidents, traffic congestion, and air pollution. The main cause of these problems is a noticeable growth in the number of vehicles. The easiest way to mitigate these problems is to build new road infrastructures unless resources such as time, money, and space are limited. Therefore, there is a need to manage the existing road infrastructures effectively and safely. In this paper, we propose a road reservation scheme that provides fast and safe response for emergency vehicles using ubiquitous sensor network. Our idea is to allow emergency vehicle to reserve a road on a freeway for arriving to the scene of the accident quickly and safely. We evaluate the performance by three reservation method (No, Hop, and Full) to show that emergency vehicles such as ambulances, fire trucks, or police cars can rapidly and safely reach their destination. Simulation results show that the average speed of road reservation is about 1.09 ~ 1.20 times faster than that of non-reservation at various flow rates. However, road reservation should consider the speed of the emergency vehicle and the road density of the emergency vehicle processing direction, as a result of Hop Reservation and Full Reservation performance comparison analysis. We confirm that road reservation can guarantee safe driving of emergency vehicles without reducing their speed and help to mitigate traffic congestion.