• Journal of the Korean Data and Information Science Society
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• v.21 no.5
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• pp.863-871
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• 2010

Until now, many studies related circular data are carried out, but the focuses are mainly on mildly peaked symmetric or asymmetric cases. In this paper we studied a modeling process for sharply peaked asymmetric circular data. By using wrapped Laplace, which was firstly introduced by Jammalamadaka and Kozbowski (2003), and its mixture distributions, we considered the model fitting problem of multi-modal circular data as well as unimodal one. In particular we suggested EM algorithm to find ML estimates of the mixture of wrapped Laplace distributions. Simulation results showed that the suggested EM algorithm is very accurate and useful.

• The Transactions of the Korea Information Processing Society
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• v.6 no.9
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• pp.2558-2562
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• 1999

This paper proposes on the methods of noise removal and edge extraction which is done by eliminating the ambiguities of the image using normalization and minimizing the entropy. Pre-existing methods have their own peculiarities and limitations, such as gray level distributions change very slowly or two regions which having similar gray level distribution are touched. This affects on the post processing such as feature extraction, as a result, this leads to false-recognition or no-recognition. Therefore, this paper proposes on the methods which overcome these problems. Finally, the effectiveness of this paper is demonstrated by several experiments.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.36-36
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• 2021

최근 기후변화로 인한 집중홍우 등으로 홍수 등 재난이 증가하고 있으며, 이를 과학적으로 조사하고 분석하기에는 공간적으로 범위가 넓다. 특히, 미계측유역은 자료를 수집하고 정량적으로 분석 및 예측하는 데에는 한계가 많은 실정이다. 따라서 본 연구에서는 위성영상 자료를 활용하여, 하천폭, 수면경사, 수위 등 자료를 추출하고, 이를 유량조사를 수행한 지점의 자료와 비교하여 수리 기하적 상관성을 분석하였다. 특히, 하도특성을 고려하여 중·하류로 구분하고 유량과 수리기하 학의 관계를 분석하였다. 위성영상 중 취득이 용이한 Sentinel 자료를 선별하여 수리특성인자를 추출하였다. 영상자료의 해상도가 20 m이며, 자료의 한계에 따른 하천폭, 경사, 수위에 대한 유효 기준을 제시하고 경사가 완만하고 하폭이 넓은 대하천에 적용하였다. 그리고, 하천수리인자 특성을 입력변수로 하는 유량을 추정하기 위한 회귀모형을 구축하고, 모의유량과 실측유량을 비교하여 그 적용성을 평가하였다. 개발된 모형은 규모가 유사한 시험유역을 미계측 유역으로 간주하여 평균제곱근오차(RMSE) 와 평균절대오차(MAE)를 이용하여 정확도를 추정하였다. 본 연구를 통해 주요하천의 수리기하 특성을 통계화하고 유량과의 특성을 도출하여 국내하천의 특성을 범주화 할 수 있었고, 미계측 유역에서의 유량을 원격탐사와 같은 간접적인 방법을 통해 추정하고 적용할 수 있을 것으로 기대된다.

• International Area Studies Review
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• v.16 no.3
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• pp.77-97
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• 2012

Estimated coefficients has serious problems including inconsistency, biasness, etc. because many researches about the effect of fiscal decentralization on a country's economic growth use the traditional OLS method. Researches use the data intactly so that so called "spurious regression" phenomenon exists. This causes fundamental fallacy. This research tries unit root test, cointegration test, and then estimates the United States' economic time series by using VECM. The analysis of the effect of the state level-fiscal decentralization on economic growth shows two long term-equilibriums. During short term-dynamic adjustment, fiscal decentralization and economic growth move the same or different directions. In case of prediction GDP increases steeply and then from 2015 gently; and fiscal decentralization index shows a general reduction trend and then decreases slowly. At local level it shows two long term-equilibriums. During short term-dynamic adjustment, fiscal decentralization and economic growth also move the same or different directions. Impulse response analysis shows the very negative effect of fiscal decentralization on economic growth.

• The Korean Journal of Food And Nutrition
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• v.15 no.1
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• pp.1-6
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• 2002

This study was conducted to investigate the effects of vacuum packaging on lipid oxidation and meat color of chilled pork. During storage meats wert evaluated for TBA values, pH, blooming time and CIE L$\^$*/a$\^$*/b$\^$*/ values. The TBA values of wrapped meats increased rapidly after 7days and Those of vacuum packaged meats maintained at low level up to 30 days of storage. The pH of wrapped meats increased rapidly after 7days, while those of vacuum packaged meats increased slowly up to 30 days of storage. The bloom time of vacuum packaged meals was 30 min after opening. The CIF L$\^$*/ values of wrapped meats decreased rapidly on the 7th day, while those of vacuum packaged meats directly after opening decreased slightly up to 7days of storage and thereafter increased gradually. The CIE a$\^$*/ values of wrapped meats increased gradually up to 7days and thereafter decreased rapidly, while those of vacuum packaged meats directly after opening were lower than those of wrapped meats. The CIE a$\^$*/ values of vacuum packaged meats after 30 min in the air were higher than those of vacuum packaged meals directly after opening. The CIE b$\^$*/ values of wrapped meats increased rapidly on 4th day and thereafter decreased rapidly, while those of vacuum packaged meats directly after opening were lower than those of wrapped meats. The CIE b$\^$*/ values of vacuum packaged meats after 30 min in the air were higher than those of vacuum packaged meats directly after opening.

• Food Engineering Progress
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• v.15 no.4
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• pp.382-387
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• 2011

Physicohemical properties of dual-modified rice starches, cross-linked (with $POCl_{3}$) and hydroxypropylated (with propylene oxide) rice starches, were studied. Rice starch was cross-linked using $POCl_{3}$ (0.005%, 0.02% (v/w)) at 45$^{\circ}C$ for 2 hr and then hydroxypropylated using propylene oxide (2%, 6%, 12% (v/w)) at 45$^{\circ}C$ for 24 hr, respectively. Swelling power, solubility, thermal properties (DSC) and pasting properties (RVA) of cross-linked and hydroxypropylated (CLHP) rice starches were determined. Swelling power of CLHP rice starch increased at relatively lower temperature than native rice starch. Solubility of CLHP rice starch was lower than that of native rice starch. Peak viscosity of CLHP rice starch was lower than that of native starch while holding strength and final viscosity were increased with modification. Breakdown value was lower and setback value was higher than native rice starch. DSC thermal transitions of CLHP rice starch shifted toward lower temperature. Amylopectin-melting enthalpy of CLHP rice starch decreased, whereas it was not affected by the amount of $POCl_{3}$.

• Journal of Embryo Transfer
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• v.19 no.1
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• pp.61-66
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• 2004

한국 재래산양 체내수정란 생산에 대한 발정동기화 및 과배란 유도방법과 회수된 수정란의 동결 융해 후 생존율을 조사하였다. 발정동기화를 위해 CIDR+FSH 및 CIDR+PMSG의 방법을 이용한 결과, 배란점 및 회수된 수정란의 수는 CIDR+FSH 처리구에서 16.3개 및 9.4개, CIDR+PMSG 처리구에서 16.4개 및 8.7개를 나타내어 두 처리구간에 유의적 차이는 인정되지 않았다. 회수된 수정란을 형태학적으로 평가한 결과 CIDR+FSH 처리구에서 Gade A, B, C 및 D는 75.8%, 15.2%, 4.5% 및 4.5%를 나타낸 반면 CIDR+PMSG 처리구에서는 52.5%, 16.4%, 16.4% 및 14.8%였으며, 이식 가능한 수정란 (Grade A, B) 수는 CIDR+FSH 처리구가 유의적(P<0.05)으로 높게 나타났다. 회수된 수정란의 완만 동결 융해 후 생존성은 CIDR+FSH 처리구에서 73.3%, CIDR+PMSG 처리구에서 63.3%이었으며, 두 군간의 유의적차이는 인정되지 않았다. 따라서 본 결과는 한국 재래산양 체내수정란의 생산과 회수된 수정란의 보존을 위해서 CIDR+FSH로 발정동기화 시키는 것이 효과적이었다.

• Korean Journal of Environmental Agriculture
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• v.14 no.3
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• pp.345-350
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• 1995

Another two different small composters with the double layer walls(Type 3 and Type 4) were made for dwelling house. One was insulated(Type 4) but the other uninsulated(Type 3). The change in microbial flora has been investigated through laboratory composting using these composters. The results were summarized as follows. 1. While the number of mesophilic bacteria decreased, that of thermophilic bacteria increased in winter. But thermophillic bacteria and mesophillic bacteria showed a tendency to increased in winter. But thermophilic bacteria and mesophillic bacteria showed a tendency to increase and decreas simultaneously in spring and summer at the early stage of composting. 2. The number of mesophilic actinomycetes ans thermophilic actinomycetes were decreased after I week in winter, while thermophilic actinomycetes rapidly increased in spring and mildly increased in summer. 3. The number of mesophilic fungi and thermophilic fungi had a tendency to increase and decrease simultaneously at an early stage of composting except after I week in winter. 4. Mesophilic bacteria, actinomycetes and fungi showed no difference in the number of microbes, but the number of fungi in spring was smaller than in other sensons. 5. At the late stage of composting process, the number of mesophilic fungi was decreased in winter and summer but increased in spring.

• Applied Biological Chemistry
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• v.49 no.1
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• pp.49-54
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• 2006

Physicochemical properties of cross-linked rice starches were investigated. Swelling power of cross-linked rice starch increased at relatively lower temperature $(60^{\circ}C)$ than native rice starch $(70^{\circ}C)$. Cross-linked rice starch showed lower solubility $(1.7{\sim}6.1%)$ than native rice starch $(2.2{\sim}13.8%)$ and solubility is not significantly different with the amount of phosphorus oxychloride. Pasting temperature $(69.2{\sim}70.6^{\circ}C)$ and peak viscosity $(2,874{\sim}3,175\;cp)$ of cross-linked rice starch were lower than native starch $(71.6^{\circ}C,\;3,976\;cp)$, but holding strength $(2,177{\sim}2,708\;cp)$ and final viscosity $(3,424{\sim}3,826 \;cp)$ of cross-linked rice starch were higher than native starch (1,000 cp, 2,312 cp). DSC thermal transitions of cross-linked rice starches were shifted to a lower temperature than native rice starch but there was no significant difference in gelatinization enthalpy between native and cross-linked rice starches. X-ray diffraction pattern of both native and cross-linked rice starches showed typical A-type crystal indicating that cross-linking had not affected the crystalline region of starch.

• The Korean Journal of Financial Management
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• v.20 no.2
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• pp.95-126
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• 2003

This paper introduces multifractal processes and presents the empirical investigation of the multifractal asset pricing. The multifractal stock price process contains long-tails which focus on Levy-Stable distributions. The process also contains long-dependence, which is the characteristic feature of fractional Brownian motion. Multifractality introduces a new source of heterogeneity through time-varying local reqularity in the price path. This paper investigates multifractality in stock prices. After finding evidence of multifractal scaling, the multifractal spectrum is estimated via the Legendre transform. The distinguishing feature of the multifractal process is multiscaling of the return distribution's moments under time-resealing. More intensive study is required of estimation techniques and inference procedures.