• Journal of the Institute of Electronics Engineers of Korea SD
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• v.48 no.10
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• pp.46-53
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• 2011

This paper presents an equalizer reducing CCI(cell-to-cell interference) in MLC NAND flash memory. The CCI is a critical factor which affects occurring data errors in a cell, when surrounding cells are programed. We derived a characteristic equation for CCI considering write procedure of data that is similar with signal equalizing. The model considers the floating gate capacitance coupling effect, the direct field effect, and programming methods of the MLC NAND flash memory. We verify the proposed equalizer comparing with the measured data of 1-block MLC NAND flash memory. As the simulation result, the equalizer shows an error correction ratio about 60% under 20nm NAND process.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.3
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• pp.263-269
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• 1995

To determine the autochthonous COD caused by the production of phytoplankton, three different methods were used simultaneously utilizing several environmental factors and applied to the Nakdong Estuary. From the estimation of the tropic state index, tropic level in the Nakdong Estuary was found to be in excess of eutrophication level at all area studied. The percentage of autochthonous COD in total COD was largest in summer and in station No. 6 $(43.5\%)$. Using of the relationship between COD and salinity was not appropriate tov the evaluation of the autochthonous COD due to discrepancy with other tesulfs evaluated. However, the evaluations of autochthonous COD obtained from the $\DeltaCOO$ and the relationship between COD and chl.a were found to be proper methods, resulting in a relative error less than $20\%$ for all of the area investigated.

• Journal of Korean society of Dental Hygiene
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• v.16 no.6
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• pp.863-877
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• 2016

The study aimed to investigate the influence of perceived patient safety culture on patient safety management activity in the dental hygienists. Methods: A self-reported questionnaire was completed by 292 dental hygienists in Seoul, Incheon and Gyeonggido from March 1 to April 8, 2016. The questionnaire consisted of general characteristics of the subjects (9 items), patient safety culture (44 items), and patient safety management activity (25 items) by Likert 5 point scale. Data were analyzed by t test, one way ANOVA, stepwise multiple regression test, and post-hoc Tukey test using SPSS 18.0 program. Results: The perceived patient safety culture was 3.50 on average. Entire organization was the highest score (3.68) and followed the communication process (3.55), the environment of work unit (3.47), the attitude of supervisor/manager (3.45), and the frequency of events reported (2.98). The average of patient safety management activity was 3.71. As for the factors of patient safety culture on patient safety management activity, communication process was the most influential factor (${\beta}=0.268$), and followed the entire organization (${\beta}=0.265$), the environment of work unit (${\beta} =0.166$), the frequency of events reported (${\beta}=0.104$), and among the control variables. Work place proved to be the only significant variable. Conclusions: In order to promote patient safety management activity of dental institutions, the patient safety culture should be created and established. The influence of communication process and patient safety culture at entire organization level was huge. So the environment of work unit and the perceived patient safety culture in the process of reported events were influencing factors. The strategy for patient safety management activity should be considered because of low level of perceived patient safety culture.

• Korean Journal of Remote Sensing
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• v.28 no.6
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• pp.635-651
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• 2012

To produce a level-3 monthly composite image from daily level-2 Sea-viewing Wide Field-of-view Sensor (SeaWiFS) chlorophyll-a concentration data set in the East Sea, we applied four average methods such as the simple average method, the geometric mean method, the maximum likelihood average method, and the weighted averaging method. Prior to performing each averaging method, we classified all pixels into normal pixels and abnormal speckles with anomalously high chlorophyll-a concentrations to eliminate speckles from the following procedure for composite methods. As a result, all composite maps did not contain the erratic effect of speckles. The geometric mean method tended to underestimate chlorophyll-a concentration values all the time as compared with other methods. The weighted averaging method was quite similar to the simple average method, however, it had a tendency to be overestimated at high-value range of chlorophyll-a concentration. Maximum likelihood method was almost similar to the simple average method by demonstrating small variance and high correlation (r=0.9962) of the differences between the two. However, it still had the disadvantage that it was very sensitive in the presence of speckles within a bin. The geometric mean was most significantly deviated from the remaining methods regardless of the magnitude of chlorophyll-a concentration values. Its bias error tended to be large when the standard deviation within a bin increased with less uniformity. It was more biased when data uniformity became small. All the methods exhibited large errors as chlorophyll-a concentration values dominantly scatter in terms of time and space. This study emphasizes the importance of the speckle removal process and proper selection of average methods to reduce composite errors for diverse scientific applications of satellite-derived chlorophyll-a concentration data.

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

• Journal of the Korean Society of Radiology
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• v.8 no.1
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• pp.19-26
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• 2014

This paper suggests techniques to enhance coding time which is a problem in traditional fractal compression and to improve fidelity of reconstructed images by determining fractal coefficient through adaptive selection of block approximation formula. First, to reduce coding time, we construct a linear list of domain blocks of which characteristics is given by their luminance and variance and then we control block searching time according to the first permissible threshold value. Next, when employing three-level block partition, if a range block of minimum partition level cannot find a domain block which has a satisfying approximation error, we choose new approximation coefficients using a non-linear approximation of luminance term. This boosts the fidelity. Our experiment employing the above methods shows enhancement in the coding time more than two times over traditional coding methods and shows improvement in PSNR value by about 1-3dB at the same compression rate.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.15 no.2
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• pp.165-173
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• 1997

The combined bundle block adjustment with projection center coordinates determined by kinematic DGPS-positioning has reached a high level of accuracy. Standard deviations of the ground coordinates of $\pm{10cm}$ or even better can be reached. On this accuracy level also smaller error components are becoming more important. One major point of this is the interpolation of the projection centers as a function of time between the GPS-antenna locations. A just linear interpolation is not respecting the not linear movement of the aircraft. Based on a least squares polynomial fitting the aircraft maneuver can be estimated more accurate and blunders of the GPS-positions caused by loss of satellite and cycle slips are determinable. The interpolation with a time interval of 3sec in the study area RHEINKAMP is quite different to the interpolation with a time interval of 6-7sec in the study area MAAS. The GPS-positions of the study area are identified as blunders based on a local polynomial regression. This cannot be neglected for precise block adjustment.

• Journal of the Korean Society of Radiology
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• v.10 no.4
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• pp.263-270
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• 2016

This paper suggests techniques to enhance coding time which is a problem in traditional fractal compression and to improve fidelity of reconstructed images by determining fractal coefficient through adaptive selection of block approximation formula. First, to reduce coding time, we construct a linear list of domain blocks of which characteristics is given by their luminance and variance and then we control block searching time according to the first permissible threshold value. Next, when employing three-level block partition, if a range block of minimum partition level cannot find a domain block which has a satisfying approximation error, There applied to 24-bpp color image compression and image techniques. The result did not occur a loss in the image quality of the image when using the encoding method, such as almost to the color in the YIQ image compression rate and image quality, such as RGB images and showed good.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.8
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• pp.706-711
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• 2015

The fighter aircraft uses several different loading configurations for air-to-surface and air-to-air combat missions. To maintain wings-level flight with an asymmetric weapon configuration, a pilot controls a roll trim system. However, it is difficult to apply an accurate roll trim input for wings-level flight in the actual flight under disturbance. The inaccurate roll trim input degrades the performance of the roll autopilot system. In this paper, to solve this problem, an integrator was additionally designed in the command part of the roll autopilot system. The initial transient response was improved by scheduling the limiter to restrict the roll attitude error. As a result of the evaluation of the simulation for the designed flight control law, the roll attitude following performance was found to be improved in the autopilot system operation under the inaccurate roll trim condition.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.21 no.5
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• pp.380-390
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• 2009

This study was conducted as a part of investigating pre-reclamation shorelines from aerial photographs to estimate coastal land area at reclaimed lands (Anjeong industrial complex, Myeongji residental complex, and Noksan industrial complex), southeastern coast of Korea. To assess how the shorelines were suitable for the calculation of coastal lands, we constructed shoreline change data. Secondary ground control points were used to accomplish triangulation for old aerial photographs. Two kinds of shorelines were mapped; one was the shoreline based on approximately highest high water level (AHHWL) and the other was the high water line based on wet/dry signiture. These shorelines were consistent at artificial coast. Shoreline change data were built with a variety of levels of error due to detailed differences in the photograph scale, quality of image, type of ground control point and type of shoreline. Thus assessment of the pre-reclamation shorelines at the level of qualitative analysis for the trend of shoreline changes was satisfactory. Most of shoreline changes before reclamation in this study were associated with coastal development. Investigation of shoreline attributes in relation to aerial photographs allowed us to understand the shoreline changes.