• Title/Summary/Keyword: Association model

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Time-lapse crosswell seismic tomography for monitoring injected $CO_2$ in an onshore aquifer, Nagaoka, Japan (일본 Nagaoka의 육상 대수층에 주입된 $CO_2$의 관찰을 위한 시간차 시추공간 탄성파 토모그래피)

  • Saito, Hideki;Nobuoka, Dai;Azuma, Hiroyuki;Xue, Ziqiu;Tanase, Daiji
    • Geophysics and Geophysical Exploration
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    • v.9 no.1
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    • pp.30-36
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    • 2006
  • Japan's first pilot-scale $CO_2$ sequestration experiment has been conducted in Nagaoka, where 10400 t of $CO_2$ have been injected in an onshore aquifer at a depth of about 1100 m. Among various measurements conducted at the site for monitoring the injected $CO_2$, we conducted time-lapse crosswell seismic tomography between two observation wells to determine the distribution of $CO_2$ in the aquifer by the change of P-wave velocities. This paper reports the results of the crosswell seismic tomography conducted at the site. The crosswell seismic tomography measurements were carried out three times; once before the injection as a baseline survey, and twice during the injection as monitoring surveys. The velocity tomograms resulting from the monitoring surveys were compared to the baseline survey tomogram, and velocity difference tomograms were generated. The velocity difference tomograms showed that velocity had decreased in a part of the aquifer around the injection well, where the injected $CO_2$ was supposed to be distributed. We also found that the area in which velocity had decreased was expanding in the formation up-dip direction, as increasing amounts of $CO_2$ were injected. The maximum velocity reductions observed were 3.0% after 3200 t of $CO_2$ had been injected, and 3.5% after injection of 6200 t of $CO_2$. Although seismic tomography could map the area of velocity decrease due to $CO_2$ injection, we observed some contradictions with the results of time-lapse sonic logging, and with the geological condition of the cap rock. To investigate these contradictions, we conducted numerical experiments simulating the test site. As a result, we found that part of the velocity distribution displayed in the tomograms was affected by artefacts or ghosts caused by the source-receiver geometry for the crosswell tomography in this particular site. The maximum velocity decrease obtained by tomography (3.5%) was much smaller than that observed by sonic logging (more than 20%). The numerical experiment results showed that only 5.5% velocity reduction might be observed, although the model was given a 20% velocity reduction zone. Judging from this result, the actual velocity reduction can be more than 3.5%, the value we obtained from the field data reconstruction. Further studies are needed to obtain more accurate velocity values that are comparable to those obtained by sonic logging.

The Prognostic Significance of the Number of Resected Lymph Nodes in Gastric Cancer Patients (근치 절제술을 시행한 위암에서 절제림프절 수의 임상적 의의)

  • Kim, Se-Jin;Jang, You-Jin;Kim, Jong-Han;Park, Sung-Soo;Park, Seong-Heum;Kim, Seung-Ju;Mok, Young-Jae;Kim, Chong-Suk;Ahn, Hyong-Gin
    • Journal of Gastric Cancer
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    • v.9 no.4
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    • pp.246-255
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    • 2009
  • Purpose: The objectives of this study were to investigate the impact of the number of resected lymph nodes on the survival of gastric cancer patients who underwent curative resection, and to evaluate the cut-off values that can have an influence on survival on the tumor stage-stratified analysis. Materials and Methods: The subjects were 949 gastric cancer patients who underwent curative resection at Korea University Medical Center from 1992 to 2002. They were classified according to the depth of tumor invasion, and the influence of the number of resected lymph nodes on survival was investigated. The cut-off value for the number of resected lymph nodes was determined as the smallest value that showed a significant survival difference. Results: The tumor size, location, lymph node stage, the number of metastatic lymph nodes and the number of resected lymph nodes were significantly different according to the tumor stage. The average number of resected lymph nodes was about 39, and it showed linear correlation with the number of metastatic lymph nodes. On the Cox proportional hazard model, the cut-off values of the number of resected lymph nodes, as corrected by the number of metastatic lymph nodes, was 14 for all the patients, 15 for the pT1 patients, 28 for the pT2 patients and 37 for the pT3 patients, respectively. Conclusion: Retrieving a number of lymph nodes that is more than the cut-off value could improve the survival of gastric cancer patients. Surgeons should also make efforts to perform an exact and thorough D2 lymph node dissection. Therefore, we urge surgeons to perform D2 dissection and pathologists should examine an certain exact number of lymph nodes.

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A Case Study on the Effectiveness of the Cooperative Management by Leading of Forest Owners and Its Extension System - A demonstrational cooperative management in the private forest guided by the Korean German Forest Management Project - (산주주도형(山主主導型) 협업경영사업(協業經營事業)과 그 지도체계(指導體系)의 효과(效果)에 대한 사례연구(事例硏究) -한독기구(韓獨機構) 사유림협업경영(私有林協業經營) 시범사업(示範事業)을 중심(中心)으로-)

  • Kim, Jong Kwan
    • Journal of Korean Society of Forest Science
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    • v.67 no.1
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    • pp.17-27
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    • 1984
  • The Yangsan Forest Management Station (YFMS) of Korean German Forest Management Project (KGFMP), working with the 6 legal villages of Uljugun, Kyongnam, led the forest owners in the area to organize the Forest Management Cooperative (FMC) voluntairily for improvement of private forest management and fostered it as a model from May 1975 to Apr. 1984. YFMS sent out FMC a forest manager as a forestry expert carrying out the leading extension program at the equal position with forest owners and gave FMC financial, administrative and technical assitances. During the 6 years from 1977 to 1982, 4 FMC were founded and are being operated democratically. 228 forest owners have taken the membership of their own free will and the forestland of the members covers 2,567 ha equivalent to 57% of the total private forest in the area. During the period the total area of the planting and tending is 4,185 ha, this means that a member executed 3.1 ha of forest operations per year in average, showing the high willingness on forest operations. In addition the joint works have resulted in the joint properties equivalent to 27 million Won and it will be an important foundation for operation of FMC which is a forest owners's cooperative organization for improvement of private forest management in this area. The total expenditure spent for the fostering of FMC amounted to 497,587 thousand Won and 58% of them were charged from KGFMP funds, 27% from the forest owners and 15% from public funds. The expenditure for investment was 273,104 thousand Won and 59% of the sum were appropriated as subsidies at the national level. The forest owners charged 43% of that and this means that each member invested approximately 100 thousand Won to his forestland per year in average. For the extension program 169,503 thousand Won were spent and it can be explained that 5,885 Won were spent per ha a year. The organization of FMC operated autonomously in a democratic way and the horizontal and leading extension system, which aspects the human rights, were very much effective in fostering the cooperative organization of forest owners for improvement of private forest management.

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Formulation of a reference coordinate system of three-dimensional head & neck images: Part II. Reproducibility of the horizontal reference plane and midsagittal plane (3차원 두부영상의 기준좌표계 설정을 위한 연구: II부 수평기준면과 정중시상면의 재현성)

  • Park, Jae-Woo;Kim, Nam-Kug;Chang, Young-Il
    • The korean journal of orthodontics
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    • v.35 no.6 s.113
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    • pp.475-484
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    • 2005
  • This study was performed to investigate the reproducibility of the horizontal and midsagittal planes, and to suggest a stable coordinate system for three-dimensional (3D) cephalometric analysis. Eighteen CT scans were taken and the coordinate system was established using 7 reference points marked by a volume model, with no more than 4 points on the same plane. The 3D landmarks were selected on V works (Cybermed Inc., Seoul, Korea), then exported to V surgery (Cybermed Inc., Seoul, Korea) to calculate the coordinate values. All the landmarks were taken twice with a lapse of 2 weeks. The horizontal and midsagittal planes were constructed and its reproducibility was evaluated. There was no significant difference in the reproducibility of the horizontal reference planes, But, FH planes were more reproducible than other horizontal planes. FH planes showed no difference between the planes constructed with 3 out of 4 points. The angle of intersection made by 2 FH planes, composed of both Po and one Or showed less than $1^{\circ}$ difference. This was identical when 2 FH planes were composed of both Or and one Po. But, the latter cases showed a significantly smaller error. The reproducibility of the midsagittal plane was reliable with an error range of 0.61 to $1.93^{\circ}$ except for 5 establishments (FMS-Nc, Na-Rh, Na-ANS, Rh-ANS, and FR-PNS). The 3D coordinate system may be constructed with 3 planes; the horizontal plane constructed by both Po and right Or; the midsagittal plane perpendicular to the horizontal plane, including the midpoint of the Foramen Spinosum and Nc; and the coronal plane perpendicular to the horizontal and midsagittal planes, including point clinoidale, or sella, or PNS.

The pattern of movement and stress distribution during retraction of maxillary incisors using a 3-D finite element method (상악 전치부 후방 견인 시 이동 양상과 응력 분포에 관한 삼차원 유한요소법적 연구)

  • Chung, Ae-Jin;Kim, Un-Su;Lee, Soo-Haeng;Kang, Seong-Soo;Choi, Hee-In;Jo, Jin-Hyung;Kim, Sang-Cheol
    • The korean journal of orthodontics
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    • v.37 no.2 s.121
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    • pp.98-113
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    • 2007
  • Objective: The purpose of this study was to evaluate the displacement pattern and the stress distribution shown on a finite element model 3-D visualization of a dry human skull using CT during the retraction of upper anterior teeth. Methods: Experimental groups were differentiated into 8 groups according to corticotomy, anchorage (buccal: mini implant between the maxillary second premolar and first molar and second premolar reinforced with a mini Implant, palatal: mini implant between the maxillary first molar and second molar and mini implant on the midpalatal suture) and force application point (use of a power arm or not). Results: In cases where anterior teeth were retracted by a conventional T-loop arch wire, the anterior teeth tipped more postero-inferiorly and the posterior teeth moved slightly in a mesial direction. In cases where anterior teeth were retracted with corticotomy, the stress at the anterior bone segment was distributed widely and showed a smaller degree of tipping movement of the anterior teeth, but with a greater amount of displacement. In cases where anterior teeth were retracted from the buccal side with force applied to the mini implant placed between the maxillary second premolar and the first molar to the canine power arm, it showed that a smaller degree of tipping movement was generated than when force was applied to the second premolar reinforced with a mini implant from the canine bracket. In cases where anterior teeth were retracted from the palatal side with force applied to the mini implant on the midpalatal suture, it resulted in a greater degree of tipping movement than when force was applied to the mini implant between the maxillary first and second molars. Conclusion: The results of this study verifies the effects of corticotomies and the effects of controlling orthodontic force vectors during tooth movement.

Associations between Characteristics of Green Spaces, Physical Activity and Health - Focusing on the Case Study of Changwon City - (공원녹지의 특성과 신체활동 및 건강의 상호관련성 - 창원시를 대상으로 -)

  • Baek, Su-Kyeongq;Park, Kyung-Hun
    • Journal of the Korean Institute of Landscape Architecture
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    • v.42 no.3
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    • pp.1-12
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    • 2014
  • Urban Green space takes charge of the important role for the physical activity and promotion of health to the residents. Therefore, this study is trying to examine the relationship between the various characteristics of green space and green space usage for physical activity and health promotion. A questionnaire survey was conducted to obtain the information about patterns of green space usage and perceived neighborhood environments for the residents living in Changwon-si, Gyeongsangnam-do(n=541). Geographic Information System(GIS) was used to construct spatial data about green space accessibility and physical neighborhood environments. A Multiple Linear Regression model was used to examine the association between the characteristics of green space and physical activity, perceived health status and BMI(Body Mass Index). The study results revealed that the residents' physical activities are positively and directly influenced by the number of available public parks and green spaces in the vicinity(${\leq}200m$). The frequency at which residents witness others exercising nearby or the perceived abundance of low-cost gym facilities also factor as positive influences. The closer to the park, the higher the number of parks and area of green spaces, the more comfortable the walk thereto and the denser the neighboring residential area distribution, the perceived health level was found to be the more positively influenced. Further, it was verified that BMI is correlated with the number of public parks and green spaces within 400 m of the resident's home as well as the safety of walkways, the density of neighboring residential areas, the ratio of road, and the density of crosswalk. The significant multiple regression models between the characteristics of green spaces and physical activities and perceived health level were extracted within the significance level of 10%. This study will contribute to provide better understanding the ways in which green space and neighborhood characteristics are associated with physical activity and health. The result of this research will be available in the landscape architecture plan aimed at improving the use of green space for physical activity and reducing obesity.

Studies on the Epidemiological Change of Clonorchiasis After Mass Chemotherapy in Highly endemic Areas (집단치료사업에 따른 간흡충증의 역학적 변동에 관한 조사)

  • Joo, Kyoung-Hwan;Chu, Paul B.;Rim, Han-Jong;Lee, Joon-Sang
    • Journal of agricultural medicine and community health
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    • v.12 no.1
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    • pp.80-93
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    • 1987
  • Mass chemotherapy of Clonorchis sinensis infection in Korea was started in 1982 with 40mg/kg body weight single dose administration scheme of praziquantel. The purpose of this study was to investigate the efficiency of current mass chemotherapy project and compare the epidemiological changes in endemic area of Ckmorchis sinensis. This study was performed at Kimhae-city and Samrangjin-eup of Miryang-gun, Kyongnam province, highly endemic area of C. sinensis located southeastern part of Korea from July to October of 1986. The therapy project of Kimhae area was performed in 1984, whereas that of Samrangjin was done in 1985 by stool examination of the Korea Association for Parasite Eradication(KAPE) and drug administration of local health centre. The results obtained were as follows; 1) As a results of stool examination from 234 specimens obtained in Kimhae area, the infection rate has decreased to 34.2%from 45.6p in 1983, but the infection rate of C. sinensis from 341 specimens obtained in Samrangjin area did not decrease (58.1%in 1986 490%in 1983). 2) The study in Kimhae area showed that the average EPG decreased remarkably from 4,858 to 1,340 and those classified above the category of heavy infection decreased also from 14.0pp to 1.7%. The study in Samrangjin area showed that the average EPG did decrease drastically from 9,597 to 6,498 and those classified above the category of heavy infection did not go down drastically from 25.2% to 14.2%. 3) The study in Kimhae area showed decrease of Cs.$D._{50}$ in comparison to that in 1983, wheareas Cs.$D._{50}$ in Samrangjin area showed no much difference compared to that in 1983. The intensities of endemicity were represented with the regression equation calculated with the cumulative percentages of EPG count. Regression equation was Y=4.49+1.19 log x in Kimhae area and Y=3.66+127 log x in Samrangjin area. 4) The two stage catalytic model was applied and the calculation lead to the equation $Y=5.33(e^{-0.018t}-e^{-0.016t})$ in Kimhae area and $Y=1.25(e^{-0.010t}-e^{-0.018t})$ in Kimhae area and $Y=125(e^{-0.010t}-e^{-0.050t})$ in Samrangjin area 5) The infection rate of cercaria in P.manchouric-us studied in Kimhae area showed 1.25% which is not much different from that in previous years, wheareas the infection rate of metacercaria in P. parva studied in the same area this year showed 2.5-20.2/gm of flesh in comparison to 64/gm of flesh in 1983. 6) Data of C. sinensis infection on the reservoir host in Kimhae area showed 4 out of 18 dogs, 1 out of 18 rats and that in Samrangjin area showed 2 out of 18 dogs respectively. 7) Among the inhabitants who were under mass chemotherapy in Kimhae area, 71out of them, upon stool examination, showed infection rate of 66.2% and those classified above the category of heavy infection, 2.4%. In comparison to infection rate of 33.7% and those classified above the category of heavy infection, which is 1.0%, obtained from those not under mass chemotherapy showed higher infection rate and somewhat equal distribution of intensity of infection. The above statements reflect the fact that individual therapy besides mass chemotherapy was prevalent in that area. 8) On the other side, the studies in Samrangjin area showed infection rate of 68.7% and those above the category of heavy infection, which is 6.1%, in comparison to infection rate of 58.3% and those above the category of heavy infection, which is 16.5%, in those not under mass chemotherapy. the above reflects that although a good deal of inhabit-ants were classified under light or moderate infection category, those above the category of heavy infection, yet, numbered a lot, and individual chemotherapy has not been going on. In conclusion, it was suggested that the number of reinfected inhabitants among those under mass chemotherapy were numerous. Accordingly, the reinforcement of health education should be followed with mass chemotherapy. The facts of high infection rate exemplified by 65% and high number of those above the category of heavy infection in Samrangjin area say that reevaluation of dosage, number of medication and intervals should be necessarily made.

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A Study on the Nursing Performance of the Home Care Nurses in Seoul (서울지역 가정간호사의 업무수행능력 실태조사)

  • Suh, Moon-Ja;Park, Ho-Ran;Kang, Hyun-Sook;Kim, So-Sun;Shin, Kyung-Lim;Kim, Keun-Soon;Kim, Hae-Sook
    • Journal of Home Health Care Nursing
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    • v.6
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    • pp.46-58
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    • 1999
  • The purpose of this research was to find out the state of the nursing performance of the home care nurses in Seoul in order to provide the data for the practical work guide. The data were collected from fifty home care nurses working in 22 institutions located in Seoul. The research tool used for this research was modified and tested by Song Jong-Rye(1999) which was originally modified the standard tool of American Nurses Association (1998) and was partly supplement and adjusted for this research. The reliability of this tool was Cronbach's $\alpha$=.0982. The collected data were statistically processed using SAS for t-test, ANOVA. $Scheff\'{e}$ test. Among the surveyees, 50% have been working as a home care nurse more than three years and 74.0% of them were married. And 52% have B.S degree with certification of home care nurse from the certification program for Home Care Nurses affiliated at nursing schools. Half of the home care nursing organizations were based on the general hospitals, and most(78%) of the responsible senior personnels of those organizations were nurses. The following results are drawn from this research. 1) The level of nursing performance by the task sectors General performance level of home care nurses was relatively high in grade of 3.06 from total 4.00. Among the task sectors. the ethical field scored the highest points, and the next were nursing intervention, professional training, and data gathering, and the research sector scored the lowest point. 2) The level of nursing performance by general features of home care nurses Statistically relevant correlation between performance according to the duration of working experience as a nurse(p=0.8951) and performance according to the duration of working as home care nurse(p=0.2263) did not emerge. Also, performance by marriage status(p=0.2218), education(p=0.5733), and taking the certification program for home card nurse(p =0.1560) has no statistically meaningful correlation. 3) The level of nursing performance by the type of home care nursing organizations There exists a significant difference(p=0.002) between performances by the types of organizations. Most of the responsible senior personnels of the home care nursing organization were nurses. The level of nursing performance of the home care nursing organization under nurse management was relatively higher than that of home care nursing organizations led by medical doctors or non-medical professional, but this was not proved as statistically meaningful(p =0.3617). 4) The level of nursing performance by task sectors according to the characteristic of home care nursing service organization There exists a significant difference between nursing performances by task sectors according to the characteristics of home care nursing organization(p=0.002). In case of model research center of one College of Nursing, the nursing performance in the sectors of organization, theory, and data gathering were lower than that of in hospital based home care nursing service. And in case of local home care centers, performances in sectors of organization, theory, data gathering, nursing intervention. professional training, and research sectors were significantly low. Based on the obtained results, overall performance of home care nurses can be appraised as relatively good. Especially, performances in sectors of the nursing intervention, nursing plan. and data gathering including the in direct nursing were recorded high scores. From this, it can be concluded that high quality of nursing is relatively practicing for home patients at these days. Since the high quality of nursing for patients was directly related to the level of nursing performances of home care nurses, it is required to improve practical performance level of them by making constant evaluation and running continual education program and supplementing curriculum for the sectors with low scores.

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An Empirical Study of Financial Analyst's Forecasting Activities on the Firm's Operating Performances (기업실적에 대한 재무분석가의 예측활동에 관한 실증연구)

  • Kwak, Jae-Seok
    • The Korean Journal of Financial Management
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    • v.20 no.1
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    • pp.93-124
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    • 2003
  • This paper studies the financial analyst's forecasting activities on the firm's operating performance during the period from 1999 to 2003. In this study, financial analyst's forecasting activities are focused on the sales, operating income and net income and financial analyst's forecasting accuracy, forecasting revising patterns and forecasting activities to the unexpected firm's operating performance are studied. Some empirical findings in this study are as follows. First, standard estimate error on the sales, operating income and net income are all significantly negative value and so financial analyst's forecast on the firm's operating performance are upwardly biased. Second, domestic financial analyst's forecasting activities is relatively more accuracy than foreign financial analyst's forecasting activities. Third, forecasting time is more close to the end of the operating performance announcement day, forecasting activities are more accuracy. Fourth, comparing with individual financial analyst's forecast, consensus forecast is more accuracy. Fifth, in the comparative forecasting activities study according to the prior firm's operating performance, financial analyst's forecasting revision activities are found to be upward or downward. Sixth, financial analysts overreact in the sales forecast and underreact in the operating income and net income forecast. Seventh, in the empirical analysis on the Easterwood-Nutt's test model(1999) which the firm's performance change are divided into the expected performance change and the unexpected performance change, it is found that financial analyst's forecasting activities on the firm's operating performance are systematically optimistic.

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A Study on the Sensitibities of Cashflow and Growth Opportunities to Investments (기업투자와 성장기회, 현금흐름의 민감도에 관한 실증연구)

  • Lee, Won-Heum
    • The Korean Journal of Financial Management
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    • v.24 no.2
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    • pp.1-40
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    • 2007
  • We test a model of investment-cashflow-growth opportunities relationship in order to estimate the sensitivities to investments. In this study, we use a new proxy variable for the value of growth opportunities(hereafter "VGO"), which is based on the seminal papers of M&M(1958:1961:1963) and Lee(2006;2007). The empirical findings on the sensitivities of cashflow and growth opportunities are as follows. First, when the traditional proxy variables for the growth opportunities such as Tobin's Q, MBR and sales growth are included with the new proxy VGO in the estimation, their coefficients are turned out to be insignificant. Second, only the new proxy variable VGO shows a statistically significant positive sensitibity to investment, which can be regarded that the growth opportunities hold the positive influences to investments. Third, the Tobin's Q can be decomposed into three factors such as the value of growth opportunities(VGO), the value of asset-in-place and valuation errors. It turns out that only the VGO shows a statistically significant positive relationship with investment among others. This means that the new variable VGO is a good proxy variable for the growth opportunities in the investment-cashflow sensitivity analysis. In sum, thanks to the above findings in this study, we can say that it will not be proper to choose a proxy variable for the growth opportunities from the traditional set of proxies such as Tobin's Q, MBR, or sales growth rate.

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