• Journal of Korean Society for Geospatial Information Science
• /
• v.15 no.2 s.40
• /
• pp.15-23
• /
• 2007

This paper presents a shoreline change analysis on a reclaimed land, using a pair of aerial photographs taken before and after the reclamation. Shorelines that are defined by a tide datum, i.e. Approximately Highest High Water Level, were mapped by both analytical and digital photogrammetric methods. The past shorelines were overlapped with digital cadastral map from which areas of retracted and protruded lands were computed. Magnitude of shoreline changes was estimated by calculating areas between the past and present shorelines. Comparisons in terms of areas showed a fairly good agreement between the two methods. However, particularly in the estuary of complex morphology, shoreline mapping by digital photogrammetric method requires images to be scanned at a resolution higher than 1200 dpi.

• Korean Journal of Geomatics
• /
• v.5 no.1
• /
• pp.43-49
• /
• 2005

It is well known that GPS technique can be used for high accuracy leveling positioning if a precise geoid model is available to use at a surveying point. In this study, KOGD2003 geoid model was developed in and around Korean peninsula and this geoid model could be achieved by combining GPS/leveling data with the formerly developed KOGD2002. To this end, the software for orthometric height obtaining and geodetic datum transformation has been implemented with the visual C++ language, what we called GPS-GeoL v.1.0. In order to evaluate the performance and the accuracy of the software, GPS field tests were carried out in the Korean second-order leveling network over Chollabukdo area. Results of the tests have shown that the mean value of the differences between outputs of the software developed in this research and officially announced orthometric heights by NGII (National Geographic Information Institute) was 0.0221 m and also those of RMS was 0.0332 m. Therefore, it was possible to conclude that the KOGD2003 and GPS-GeoL v.1.0 software could be used to determine orthometric heights for civil construction field applications with cm-level accuracy.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
• /
• 2010.04a
• /
• pp.429-431
• /
• 2010

The hybrid geoid model should be determined by fitting the gravimetric geoid to the geometric geoid which were presented the local vertical level. Therefore, it is necessary to find firstly the optimal scheme for improving the accuracy of gravimetric geoid in order to development the high-precision hybrid geoid model. Through finding the optimal scheme for determining the each part of gravimetric geoid, the most accurate gravimetric geoid model in Korea will be developed when the EIGEN-CG03C model to degree 360, 4-band spherical FFT and RTM reduction methods were used for determining the long, middle and short-frequency part of gravimetric geoid respectively. Finally, we developed the hybrid geoid model around Korea by correcting to gravimetric geoid with the correction term. The correction term is modelled using the difference between GPS/Levelling derived geoidal heights and gravimetric geoidal heights. The stochastic model used in the calculation of correction term is the LSC technique based on second-order Markov covariance function. 503 GPS/Levelling data were used to model the correction term. The degree of LSC fitting to the final hybrid geoid model in Korea was evaluated as 0.001m ${\pm}0.054m$.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.14 no.1
• /
• pp.41-50
• /
• 2002

An attempt has been made to establish digital bathymetric and topographic database in the form of grid point value(GPV) with an interval of one-minute horizontal space fur a wide region of seas adjacent to Korean Peninsula and also with an interval of one-arcsecond for coastal seas of Korean Peninsula. Especially terrestrial and marine data fusion work using mean sea level as vertical datum plane has been performed for one-arcsecond GPV dataset. It is believed that the compiled bathymetric dataset are reliable comparing with existing dataset so for and can be utilized for ocean simulations of intermediate scale process and also detailed coastal inundation process.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 1999.10a
• /
• pp.225-233
• /
• 1999

Harbor design and construction plan in Korea becomes the most hot issue both in the Maritime Affairs and Fisheries Office and in the related port industries. Production of the plane and cross section maps together with the profile map for harbor project is done firstly and is important in all procedure because it is the most basic datum in counting the constructional expense for determination of the area and capacity. As the expense assigned on surveying part among the total expenses of harbor planning and construction in Korea is very small, it is difficult to make exact maps. Moveover, because the method used to make such maps is mostly traditional surveying such as plane table surveying , offset surveying, stadia surveying and level surveying, etc, it is difficult to get precise three dimensional maps. Therefore, for making more precise map in the harbor project, we have to use the newest surveying equipment. This study discusses the method of old surveying and recent surveying used for the three dimensional map of the site for lighthouse which gives navigational aids for the in-and out-bound ships. The authors are proposing a method for more precise three dimensional positioning in this study.

• Journal of computational fluids engineering
• /
• v.15 no.2
• /
• pp.7-13
• /
• 2010

Flight vehicles such as wheel wells and bomb bays have many cavities. The flow around a cavity is characterized as an unsteady flow because of the formation and dissipation of vortices brought by the interaction between the free stream shear layer and the internal flow of the cavity. The resonance phenomena can damage the structures around the cavity and negatively affect the aerodynamic performance and stability of the vehicle. In this study, a numerical analysis was performed for the cavity flows using the unsteady compressible three-dimensional Reynolds-Averaged Navier-Stokes (RANS) equation with Wilcox's turbulence model. The Message Passing Interface (MPI) parallelized code was used for the calculations by PC-cluster. The cavity has aspect ratios (L/D) of 5.5 ~ 7.5 with width ratios (W/D) of 2 ~ 4. The Mach and Reynolds numbers are 0.4 ~ 0.6 and $1.6{\times}10^6$, respectively. The occurrence of oscillation is observed in the "shear layer and transient mode" with a feedback mechanism. Based on the Sound Pressure Level (SPL) analysis of the pressure variation at the cavity trailing edge, the dominant frequencies are analyzed and compared with the results of Rossiter's formula. The dominant frequencies are very similar to the result of Rossiter's formula and other experimental datum in the low aspect ratio cavity (L/D = ~4.5). In the high aspect ratio cavity, however, there are other low dominant frequencies of the leading edge shear layer with the dominant frequencies of the feedback mechanism.

• Proceedings of the KSRS Conference
• /
• 2007.10a
• /
• pp.90-94
• /
• 2007

The conventional single-reference station positioning is affected by systematic errors such as ionospheric and tropospheric delay, so that the rover must be located within 10 km from the reference station in order to acquire centimeter-level accuracy. The medium-range real-time kinematic has been proven feasible and can be used for high precision applications. However, the longer of the baseline, the more of the time for resolving the integral ambiguity is required. This is due to the fact that systematic errors can not be eliminated effectively by double-differencing. Recently, network approaches have been proposed to overcome the limitation of the single-reference station positioning. The real-time systematic error modeling can be achieved with the use of GPS network. For expanding the effective range and decreasing the density of the reference stations, Land Survey Bureau, Ministry of the Interior in Taiwan set up a national GPS network. In order to obtain the high precision positioning and provide the multi-goals services, a GPS network including 66 stations already been constructed in Taiwan. The users can download the corrections from the data center via the wireless internet and obtain the centimeter-level accuracy positioning. The service is very useful for surveyors and the high precision coordinates can be obtained real time.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.24 no.4
• /
• pp.495-508
• /
• 2019

Tidal datums are key and basic information used in fields of navigation, coastal structures' design, maritime boundary delimitation and inundation warning. In Korea, the Approximate Lowest Low Water (ALLW) and the Approximate Highest High Water (AHHW) have been used as levels of tidal datums for depth, coastline and vertical clearances in hydrography and coastal engineering fields. However, recently the major maritime countries including USA, Australia and UK have adopted the Lowest Astronomical Tide (LAT) and the Highest Astronomical Tide (HAT) as the tidal datums. In this study, 1-hr interval 19-year sea level records (1999-2017) observed at 9 tidal observation stations along the west and south coasts of Korea were used to calculate LAT and HAT for each station using 1-minute interval 19-year tidal prediction data yielded through three tidal harmonic methods: 19 year vector average of tidal harmonic constants (Vector Average Method, VA), tidal harmonic analysis on 19 years of continuous data (19-year Method, 19Y) and tidal harmonic analysis on one year of data (1-year Method, 1Y). The calculated LAT and HAT values were quantitatively compared with the ALLW and AHHW values, respectively. The main causes of the difference between them were explored. In this study, we used the UTide, which is capable of conducting 19-year record tidal harmonic analysis and 19 year tidal prediction. Application of the three harmonic methods showed that there were relatively small differences (mostly less than ±1 cm) of the values of LAT and HAT calculated from the VA and 19Y methods, revealing that each method can be mutually and effectively used. In contrast, the standard deviations between LATs and HATs calculated from the 1Y and 19Y methods were 3~7 cm. The LAT (HAT) differences between the 1Y and 19Y methods range from -16.4 to 10.7 cm (-8.2 to 14.3 cm), which are relatively large compared to the LAT and HAT differences between the VA and 19Y methods. The LAT (HAT) values are, on average, 33.6 (46.2) cm lower (higher) than those of ALLW (AHHW) along the west and south coast of Korea. It was found that the S_a and N₂ tides significantly contribute to these differences. In the shallow water constituents dominated area, the M₄ and MS₄ tides also remarkably contribute to them. Differences between the LAT and the ALLW are larger than those between the HAT and the AHHW. The asymmetry occurs because the LAT and HAT are calculated from the amplitudes and phase-lags of 67 harmonic constituents whereas the ALLW and AHHW are based only on the amplitudes of the 4 major harmonic constituents.

• Journal of Elementary Mathematics Education in Korea
• /
• v.10 no.1
• /
• pp.67-87
• /
• 2006

This study is to recognize a problem in the practice of performance assessment in elementary school, and to find out some suggestive points for improvement of teaching·learning method in elementary mathematics through assessment by reducing time restriction according to assessment through the practice of self-assessment, peer-assessment and observation, and then by reflecting the results of assessment on teaching learning plan. For that, the questions of study set up are as follows ; 1. How should self-assessment and peer-assessment be applied to in elementary mathematics assessment? 2. How should the time for 'let's play an interesting game' be managed for assessment of elementary mathematics? 3. How should the results of assessment be reflected on the Process of teaching and learning of mathematics? To solve these problems, a researcher of this thesis performed self-assessment, peer-assessment on 40 students of second grade under her charge as a class teacher, and applied observation in the time management process for 'let's play an interesting game' for a semester. self-assessment was made by mathematics journal, self-assessment chart, peer-assessment was by the analysis of conversation record among students in the situations of assessment, and observation was by observation of activity when playing with the results data of play analyzed. the concrete methods of application as follows ; First, mathematics journal was applied $1{\sim}2$ times by each unit with reconstruction into the level of second grade on the basis of the preceding-study models. Second, peer-assessment was applied to the unit-assessment time and the play-activities time by the method of recording·analyzing the contents of conversation among students in the process of assessment. Third, mathematical attitude & dispositions of students making use of the self- assessment table were examined referring to the teaching learning plan. Fourth, the time management for 'let's play an interesting game' was made through the prior recognition of play method and the joyful play-activities by use of the play-plate. Assessment depended on analysis of play-activities results of students making use of an observation form. Fifth, the results of self-assessment, peer-assessment, and observation were analyzed, and then they were made use of as self-observation data, of teacher her/his self, or teaching·learning improvement data. Students' self-assessment datum (mathematics diary, self-assessment sheets, conversation contents in the process of assessment) and observation materials (check lists, Play-activity result materials, conversation contents in the process of play) obtained in the process of application was analyzed as follows ; 1. From the practice of self-assessment in form of mathematics journal, I could obtain not only datum showing how much students was understanding the learning aims by unit time and to any degree they reached but also information about their response to learning datum and favorable type of learning. 2. Assessment by self-assessment chart was useful in planning the mathematics teaching learning process because it helps ascertain mathematical attitude & dispositions of students. 3. Through the application of peer-assessment, students had the opportunity of communicating with other students looking back on his/her explaining process, and teachers could obtain basic materials for assessment of students. 4, In case of time management for 'let's play an interesting game', there was natural extension of play made through time-security by prior looking into the method of play-activity, and then, for a remained time, by making children play a new game. 5, I could easily record the activities of students by use of the observation. form, and make use of it as basic data for descriptive assessment. 6, Each kinds of data obtained from the results of assessment was helpful for securing self-observation materials in the process of teaching learning and for their betterment in mathematics subject. However, because they were in the second grade of elementary school and there was an individual difference, some students could not make use of mathematics diary or self-assessment form properly. In case of these students, assessment data would be obtained through interview or observation. And for effective operation of play, its purpose & method and matters that demand special attention when play-acting should be clearly guided. Also, when applying an effective play in addition to play activities in textbook, to lessons, interesting mathematics lessons could be guided.

• Asian Oncology Nursing
• /
• v.1 no.1
• /
• pp.44-53
• /
• 2001

Despite the advances in cancer therapy in the last 20 years, cancer continues to be a life-threatening illness, and the newly diagnosed individual faces a crisis that emphasized his or her mortality. Patients who suffer from cancer may have psychological problems, especially depression. Most tend to seek the meaning of suffering when continuing pain was experienced. Then the search for meaning, which is one of the primary needs of humans, begins. This meaning is "unique and specific" to the individual, and it must be fulfilled by the individual alone. This study was conducted to provide a basis of data for a nursing intervention program to minimize a cancer patient's suffering and to understand the relationship between life satisfaction, depression, and the meaning of suffering in cancer patients. The sample was composed of 160 cancer patients who were inpatients or outpatients of three general hospitals in Seoul. Data collections were carried out from February 25th to April 20th of 2000. The data was analyzed using a SAS program for descriptive statistics, Pearson Correlations, ANOVA, and Duncan tests. The results were as follows: 1. The scores on the depression scale ranged from 20 to 65 with a mean of 40.76 (SD 9.6) The mean score on the suffering scale was 97.72 (SD 12.7), and the score of the life satisfaction ranged from 15 to 37 with a mean of 25.51 (SD 5.2). 2. There were significant correlations between the amount of life satisfaction and depression (r=-.61, P=.00), the life satisfaction and the meaning of suffering (r=.30, p=.00), and the depression and the meaning of suffering (r=-.24, p=.00). 3. The factors influencing the depression in patients with cancer are age (F=2.52, p=.04) and education level (F=3.98, p=.00). The level of the meaning of suffering in cancer patients differed by education level (F=4.13, p=.00). Also, the level of the life satisfaction in cancer patients differed by education level (F=2.72, p=.04). In conclusion, the correlation between the depression, the meaning of suffering, and life satisfaction can be used as a concrete and practical datum for the development of nursing intervention. This may assist patients with cancer, overcome their suffering and lead to a hopeful life by understanding the meaning of suffering.