• 대한핵의학회지
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• 제27권2호
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• pp.248-255
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• 1993

To Assessment of the quantified renal uptake rates in every $^{99m}Tc$-DMSA scan tests of patients is actually difficult because of time consumption and complicated calculations required to measure the correct dose of the infused radionulide and radiation decay, the adjustment for the depth of kidney and the subtraction of background count. We've formulated two regression models for the quantified renal uptake rates[I] from the simple renal uptake rates[H] with a square shaped ROI (Region-Of-Interest) in 25 cases (Group 1) and with a kidney shaped ROI in 37 cases (Group 2), respectively. The regression model for the Group 1 was $[I]_1$=0.885 $[H]_1$-4.575 (P<0.005), and for the Group 2 was $[I]_2$=0.591 $[H]_2$-2.105 (p<0.005). The formal charts were clinically convenient to evaluate the individual renal functions in patients with $^{99m}Tc$-DMSA renal scan.

• The Journal of Asian Finance, Economics and Business
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• 제4권1호
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• pp.25-38
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• 2017

This study investigates the causal relationship between stock prices and exchange rates for six Middle Eastern countries, namely, Egypt, Iran, Jordan, Kuwait, Oman, and Saudi Arabia before and during (after) the 2007 global financial crisis for the period between January 2004 and September 2015. The sample is divided into two sub-periods, that is, the period from January 1, 2004 to September 30, 2007 and the period from October 1, 2007 to September 30, 2015, to represent the pre-crisis period and the post-crisis period, respectively. Using Vector Autoregressive (VAR) model in a multivariate framework (including two control variables, inflation rates and oil prices) the results suggest that in the case of Jordan, Kuwait and Saudi Arabia, there exists bidirectional causalities after the crisis period but not the before. The opposite status is available for the case of Iran. In the case of Oman, there is bidirectional causality between the variables of interest in both periods. The results also reveal that the relationship between stock prices and exchange rates has become stronger after the 2007 global financial crisis. Overall, the results of this study indicate that fluctuations in foreign exchange markets can significantly affect stock markets in the Middle East.

• 국제지역연구
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• 제13권3호
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• pp.309-330
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• 2009

본 연구는 실질환율변동이 경기변동에 미치는 효과를 한국과 일본에 대하여 비교분석하는데 목적을 두고 있다. 기존의 실증분석에 의하면 신흥경제국의 경우 실질환율의 상승이 경기수축효과를 가져올 수 있는 반면 선진국의 경우 경기확장효과를 가질 수 있다는 연구결과가 많다. 한국은 신흥경제국의 사례로, 일본은 선진국의 사례로 각각 선택하여 기존의 연구결과와 비교하고자 한다. 구조VAR(S-VAR)모형을 사용하여 실질금리, 실질성장률, 실질환율, 국제유가, 인플레이션율 등 5개변수의 1980년 1/4분기부터 2006년 4/4분기까지의 분기데이터에 대해 충격반응함수와 분산분해를 통해 실질환율변동의 경기변동효과를 분석하고 있다. 본 연구는 한국의 경우 실질환율의 상승이 경기수축적인 반면 일본의 경우는 반대로 경기팽창적이라는 기존의 연구결과를 다시 확인하고 있다.

• 한국수학교육학회지시리즈A:수학교육
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• 제63권1호
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• pp.19-33
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• 2024

본 연구는 중학생들의 수학 흥미와 성취도의 종단적인 변화 양상을 알아보기 위해 경기교육종단연구 4-6차년도 데이터를 분석하였다. 다변량 성장혼합모형을 이용하여 분석한 결과 학생들의 수학 흥미와 성취도의 변화 양상에 이질적인 특성이 존재함을 확인하였고, 종단적인 변화 양상에 따라 학생들을 4개의 잠재집단으로 구분하였다. 학생들은 흥미와 성취도가 모두 낮은 저수준 유형, 모두 높은 고수준 유형, 학년이 올라감에 따라 증가하는 중수준-증가 유형, 학년이 올라감에 따라 감소하는 중수준-감소 유형으로 구분되었으며, 유형마다 흥미와 성취도의 종단적인 변화 양상이 다르게 나타나는 것을 확인하였다. 또한, 다변량 성장혼합모형의 초기값과 기울기 사이의 상관관계를 분석한 결과, 수학 흥미와 성취도는 초기값뿐 아니라 변화율에 있어서도 서로 긍정적인 영향이 있는 것으로 나타났다. 잠재집단의 결정에 영향을 미치는 요인을 개인, 수업방식, 가정 변인으로 나누어 그 영향력을 살펴보았고, 학생의 교육포부와 사교육 시간은 수학 흥미 및 성취도에 긍정적인 영향을 미치며 선행학습의 경우 그 정도에 따라 영향력이 달라지는 양상을 확인하였다. 학생이 인식한 수업방식의 경우, 교수자 중심 수업은 흥미와 성취도가 높은 집단에 속할 확률을 높이고, 학습자 중심 수업은 흥미와 성취도가 낮은 집단에 속할 확률을 높이는 것으로 나타났다. 본 연구는 다변량 성장혼합모형을 통해 수학교육에서 흥미와 성취도를 비롯한 다양한 특성에 대한 학생들의 변화 양상을 분석하는 새로운 방법을 제시하였다는 점에서 의의가 있다.

• Asian Journal of Business Environment
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• 제6권1호
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• pp.19-24
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• 2016

Purpose - This paper aims to find and analyze factors that determine the flows of bilateral foreign direct investment in intra-ASEAN. It specifically focuses on the dimension of macro-economic, natural resources, human resources, and the quality of governance. Research design, data, and methodology - Data were collected from 64 bilateral relations between ASEAN nations from 2002 to 2013. Panel gravity model was utilized to find factors that determine the flows of bilateral foreign direct investment. Results - Significant factors were identified that determine the flows of bilateral foreign direct investment: GDP home country, GDP host country, real interest rate, distance, and total natural resources rent. Unexpectedly, natural resources have a negative effect. Conclusions - In a situation of increasing the flow of FDI among the countries of ASEAN, the government should control the interest rates and maintain good relations with nearby countries. The negative effect of total natural resource rents implies that ASEAN countries should not depend on their natural resources to attract foreign investments.

• Communications for Statistical Applications and Methods
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• 제10권3호
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• pp.655-663
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• 2003

The fundamental tenn structure model is based on the modelling of the short rate. It is well-known that the short rate depends on the interest rate policy of monetary authorities, especially on the official rate. Babbs and Webber(1994) modelled the tenn structure of interest rates using the official rate. They assume that the official rate follows a jump process. This reflects that the official rate infrequently changes. In this paper, we test this official tenn structure model and compare the jump-diffusion model with the pure diffusion model.

• East Asian Economic Review
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• 제24권2호
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• pp.165-184
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• 2020

Applying Ismailov and Rossi (2018), I newly construct the Korea FX uncertainty based on the density distribution of historical forecast errors. This uncertainty index properly captures the rare but significant events in the Korean currency market and provides information distinct from other uncertainty measures in recent studies. I show that 1) FX uncertainty arising from unexpected depreciation has a stronger impact on Korea-U.S. exchange rates and that 2) macro variables, such as capital flows or interest rate differentials, have predictive ability regarding Korea FX uncertainty for short horizons. These findings enable us to predict the events of sudden currency crashes and understand the Korea-U.S. exchange rate dynamics.

• 한국표면공학회지
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• 제32권3호
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• pp.281-288
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• 1999

Electrodeposited Zn-Ni alloy coatings are of particular interest for improving the corrosion resistance of steel in a number of enviornments. Of particular interest is the relationship between composition, structure and corrosion rate. This paper firstly reviews the literature regarding composition-structure relationships of Zn-Ni electrodeposits and compares them with the equilibrium phase diagram. Secondly, research was carried out on a wide range of coatings which were produced in the laboratory and their structure and corrosion rates determined. It was found that unambiguous identification of phases from XRD data can be difficult. Maximum corrosion resistance of deposits is obtained at 12-13% Ni, with a $\gamma$ phase structure and predomination of (600) and (411) reflections. Compatibility is important with regard to chromate conversion coatings.

• 한국항해항만학회지
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• 제43권2호
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• pp.134-141
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• 2019

The objective of this study was to establish whether global macroeconomic indicators affect the profitability of Korean shipping companies by using panel regression analysis. OROA (operating return on assets) and ROA (ratio of net profit to assets) were selected as proxy variables for profitability. OROA and ROA were used as dependent variables. The world GDP growth rate, interest rate, exchange rate, stock index, bunker price, freight, demand and supply of the world shipping market were set as independent variables. The size of the firm was added to the control variable. For small-sized firms, OROA was not affect by macroeconomic indicators. However, ROA was affected by variables such as interest rates, bunker prices, and size of firms. For medium-sized firms, OROA was affected by demand, supply, GDP, freight, and asset variables. However, macroeconomic indicators did not affect ROA. For large-sized firms, freight, GDP, and stock index (SCI; Shanghai Composite Index) have an effect on OROA. ROA was analyzed to be influenced by bunker price and SCI.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2014년도 춘계학술대회
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• pp.408-410
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• 2014

본 논문에서는 자동차 번호판 인식을 위해 이진화과정을 거쳐 레이블링된 이미지에서 번호판 영역을 추출하기 위한 기법을 제안한다. 자동차 번호판 인식 시스템은 지금까지 많은 연구가 이루어지고 있으며, 번호판의 인식률도 점점 높아지고 있는 추세이다. 본 논문에서는 레이블링 이미지에서 자동차 번호판 영역을 추출하기 위한 관심 영역 설정에 대한 연구를 기술하였으며 레이블링을 위한 이미지 샘플은 오츠알고리즘을 이용하여 이진화 되었다.