• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.2
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• pp.265-272
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• 2007

This proposed gamma (${\gamma}$) correction system is developed to reduce the difference between non-linear gamma curve produced by a typical formula and result produced by the proposed algorithm. In order to reduce the difference, the proposed system is using the Least Squares Polynomial which is calculating the best fitting polynomial through a set of points which is sampled. Each system is consisting of continuous several kinds of equations and having their own overlap sections to get more precise. Based on the algorithm verified by MATLAB, the proposed systems are implemented by using Verilog-HDL. This paper will compare the previous algorithm of gamma system such as Existing system with Seed Table with the latest that such as Proposed system. The former and the latter system have 1, 2 clock latency; each 1 result per clock. Because each of the error range (LSB) is $1{\sim}+1,\;0{\sim}+36$, we can how that Proposed system is improved. Under the condition of SAMSUNG STD90 0.35 worst case, each gate count is 2,063, 2,564 gates and each maximum data arrival time is 29.05[ns], 17.52[ns], respectively.

• KIPS Transactions on Software and Data Engineering
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• v.10 no.7
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• pp.279-286
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• 2021

Recently, We are carrying out a policy of physical distancing of at least 1m from each other to prevent the spreading of COVID-19 disease in public places. In this paper, we propose a method for measuring distances between people in real time and an automation system that recognizes objects that are within 1 meter of each other from stereo images acquired by drones or CCTVs according to the estimated distance. A problem with existing methods used to estimate distances between multiple objects is that they do not obtain three-dimensional information of objects using only one CCTV. his is because three-dimensional information is necessary to measure distances between people when they are right next to each other or overlap in two dimensional image. Furthermore, they use only the Bounding Box information to obtain the exact coordinates of human existence. Therefore, in this paper, to obtain the exact two-dimensional coordinate value in which a person exists, we extract a person's key point to detect the location, convert it to a three-dimensional coordinate value using Stereo Vision and Camera Calibration, and estimate the Euclidean distance between people. As a result of performing an experiment for estimating the accuracy of 3D coordinates and the distance between objects (persons), the average error within 0.098m was shown in the estimation of the distance between multiple people within 1m.

• Korean Journal of Remote Sensing
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• v.28 no.1
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• pp.69-77
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• 2012

Surface insolation is one of the major indicators for climate research over the Earth system. For the climate research, long-term data and wide range of spatial coverage from the data observed by two or more of satellites of the same orbit are needed. It is important to improve the continuity and consistency of the derived products, such as surface insolation, from different satellites. In this study, surface insolations based on Geostationary Operational Environmental Satellite (GOES-9) and Multi-functional Transport Satellites (MTSAT-1R) were compared during overlap period using physical model of insolation to find ways to improve the consistency and continuity between two satellites through comparison of each channel data and ground observation data. The thermal infrared brightness temperature of two satellites show a relatively good agreement between two satellites : rootmean square error (RMSE)=5.595 Kelvin; Bias=2.065 Kelvin. Whereas, visible channels shown a quite different values, but it distributed similar tendency. And the surface insolations from two satellites are different from the ground observation data. To improve the quality of retrieved insolations, we have reproduced surface insolation of each satellite through adjustment of the Cloud Factor, and the Cloud Factor for GOES-9 satellite is modified based on the analysis result of difference channel data. As a result, the insolations estimated from GOES-9 for cloudy conditions show good agreement with MTSAT-1R and ground observation : RMSE=$83.439W\;m^{-2}$ Bias=$27.296W\;m^{-2}$. The result improved accuracy confirms that the modification of Cloud Factor for GOES-9 can improve the continuity and consistency of the insolations derived from two or more satellites.

• The Journal of Korean Society for Radiation Therapy
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• v.27 no.1
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• pp.31-43
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• 2015

Purpose : Stereotactic body radiation therapy (SBRT) has proved its efficacy in several patient populations with primary and metastatic limited tumors. Because SBRT prescription is high dose level than Conventional radiation therapy. SBRT plan is necessary for effective Organ at risk (OAR) protection and sufficient Planning target volume (PTV) dose coverage. In particular, multi-target cases may result excessive doses to OAR and hot spot due to dose overlap. This study evaluate usefulness of Volumetric modulated arc therapy (VMAT) in dosimetric and technical considerations using Flattening filter free (FFF) beam. Materials and Methods : The treatment plans for five patients, being treated on TrueBeam STx(Varian$^{TM}$, USA) with VMAT using 10MV FFF beam and Standard conformal radiotherapy (CRT) using 15MV Flattening filter (FF) beam. PTV, liver, duodenum, bowel, spinal cord, esophagus, stomach dose were evaluated using the dose volume histogram(DVH). Conformity index(CI), homogeneity index(HI), Paddick's index(PCI) for the PTV was assessed. Total Monitor unit (MU) and beam on time was assessed. Results : Average value of CI, HI and PCI for PTV was $1.381{\pm}0.028$, $1.096{\pm}0.016$, $0.944{\pm}0.473$ in VMAT and $1.381{\pm}0.042$, $1.136{\pm}0.042$, $1.534{\pm}0.465$ in CRT respectively. OAR dose in CRT plans evaluated 1.8 times higher than VMAT. Total MU in VMAT evaluated 1.3 times increase than CRT. Average beam on time was 6.8 minute in VMAT and 21.3 minute in CRT. Conclusion : VMAT for SBRT in multi-target liver cancer using FFF beam is effective treatment techniqe in dosimetric and technical considerations. VMAT decrease intra-fraction error due to treatment time shortening using high dose rate of FFF beam.

• Journal of the Korean Institute of Landscape Architecture
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• v.43 no.2
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• pp.87-104
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• 2015

As the influence of Landscape Urbanism has grown, various criticisms on the discourse also have increased. A study on critical opinions of Landscape Urbanism is necessary to fully comprehend the theoretical structure of the discourse and its limitations. This study introduced the concept of Intension and Extension, which is used in the field of Logics and Semiotic, as an analytical tool to interpret various criticisms based on different views in a more objective and synthetic way. After examining the development of criticisms of Landscape Urbanism, 30 texts with important critiques on the theory were selected and analyzed. Criticisms can be classified as internal criticism and external criticism according to specific topics they are engaged with. The study only covers internal criticism as a research scope. The internal criticisms on Landscape Urbanism are re-categorized into topics of theory, practice and the relation between theory and practice. Vagueness of concepts and error in concepts are two types criticism related to the issue of theory. Lexical Ambiguity and Intensional Vagueness are the main causes of conceptual vagueness in Landscape Urbanism. Conceptual vagueness related with the problem of redefining an existing concept through expanding its meaning reveals a structural dilemma. There are three types of criticism included in the topic of practice: absence of practical results, form-oriented practice, and ambiguous identity in practical results. Ambiguous identity is caused by Extensional Vagueness allowing borderline cases. Because these borderline cases overlap with extensions of landscape architecture, it is hard to differentiate projects of Landscape Urbanism and those of conventional landscape architecture. Most criticisms on the relation between theory and practice raise the question on the practical method. Two types of criticism are engaged with the topic of the practical method: errors in practical methods and absence of practical methods. The absence of practical methods is a fundamental problem of Landscape Urbanism which is hard to solve by the proposed solutions. However, these structural problems are not only the weak point but also the factor that is able to prove the potentials expand the scope of Landscape Urbanism. In addition to the results of the study, internal criticisms on Landscape Urbanism should be examined in the following studies in order to predict the next direction of Landscape Urbanism.

• The Korean Journal of Nuclear Medicine Technology
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• v.22 no.2
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• pp.92-96
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• 2018

Purpose In case of nuclear medical hepatobiliary scan, To quantitatively evaluate contractility of a gallbladder, gallbladder ejection fraction (GBEF%) is calculated from anterior images using fatty meal. However, when a gallbladder and other organs overlap on an anterior image, the gallbladder ejection fraction is not accurately evaluated. In order to reduce this error, the objective of our study was to figure out whether there is a significant difference in GBEF% calculated from the anterior and right lateral images. Materials and Methods After intravenous injection of 99mTc-Mebrofenin 370 MBq to randomly 50 patients who visited our hospital, we started to examine nuclear hepatobiliary scan. Using skylight(Philips, United States), we acquired anterior and right lateral image at 10 minutes, 20 minutes, 30 minutes, 60 minutes, 90minutes after injection. Using images at 60 and 90 minutes, gallbladder ejection fraction (GBEF%) was calculated from the anterior and right lateral images using JETstream workspace. For drawing more accurate ROI, CT images were referenced and 4 radiologists calculated the GBEF% in the same image and calculated the average value. We assessed whether there was a significant difference in GBEF% calculated from the anterior and right lateral images using SPSS program(Statistical Package for the Social Science, SPSS Ver.18 Inc. USA). Results About randomly 50 patients, the average value of the GBEF% calculated from the anterior image was 63.212 and the average value of the GBEF% calculated from the right lateral image was 62.666. GBEF% decreased 0.433% on the right lateral image compared with anterior image. Result of paired sample t-test, p value is over 0.05. So, there was no significant difference in GBEF% calculated from the anterior and right lateral images. Conclusion In the case that a gallbladder and other organs are not separated on an anteior image, Right lateral image would be better to acquire more accurate GBEF% than using anterior image.