• Korean Journal of Digital Imaging in Medicine
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• v.16 no.1
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• pp.13-19
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• 2014

Purpose: FLAIR image is beneficial for the diagnosis of various bran diseases including ischemic CVS, brain tumors and infections. However the border between the legion of brain metastasis and surrounding edema may not be clear. Therefore, this study aims to investigate the practical benefits of delayed imaging by comparing the image from a patient with brain metastasis before a contrast enhancement and the image 10 minutes after a contrast enhancement. Materials and methods: Of the 92 people who underwent MRI brain metastases in suspected patients 13 people in three patients there is no video to target the 37 people confirmed cases, and motion artifacts brain metastases in our hospital June-December 2013, 18 people measurement position except for the three incorrect patient (male: 11 people, female: 7 people, average age: 60 years) in the target, test equipment, 3.0T MR System (ACHIEVA Release, Philips, I was 8ChannelSENSE Head Coil use Best, and the Netherlands). TR 11000 ms, TE 125 ms, TI2800 ms, Slice Thickness 5 mm, gap 5 mm, is a Slice number 21, the parameters of the 3D FFE, T2 FLAIR variable that was used to test, TR 8.1 ms, TE 3.7 ms, Slice number 240 I set to. The experiment was conducted by acquiring the FLAIR prior to contrast enhancement (heretofore referred to as Pre FLAIR), and acquiring the 3D FFE CE five minutes after the contrast enhancement, and recomposing the images in an axial plane of S/T 3mm, G 0mm (heretofore referred to as MPR TRA CE). Using the FLAIR 10 minutes after the contrast enhancement (heretofore referred to as Post FLAIR) and Pi-View, a retrospective study was conducted. Using MRIcro on the image of a patient confirmed for his diagnosis, the images before and after the contrast media, as well as the CNR and SNR of the MPR TRA CE images of the lesion and the site absent of lesion were compared and analyzed using a one-way analysis of variance. Results: CNR for Pre FLAIR and Post FLAIR were 34.35 and 60.13, respectively, with MPR TRA CE at 23.77 showing no significant difference (p<0.050). Post-experiment analysis shows a difference between Pre FLAIR and Post FLAIR in terms of CNR (p<0.050), but no difference in CNR between Post FLAIR and MPR TRA CE (p>0.050), indicating that the contrast media had an effect only on Pre FLAIR and Post FLAIR. The SNR for the normal site Pre FLAIR was 106.43, and for the lesion site 140.79. Post FLAIR for the normal site was 107.79, and for the lesion site 167.91. MPR TRA CE for the normal site was 140.23 and for the lesion site 183.19, showing significant difference (p<0.050), and post-experiment analysis shows that there was a difference in SNR only on the lesion sites for Pre FLAIR and Post FLAIR (p<0.050). There was no difference in SNR between the normal site and lesion site for Post FLAIR and MPR TRA CE, indicating no effect from the contrast media (p>0.050). Conclusions: This experiment shows that Post FLAIR has a higher contrast than Pre FLAIR, and a higher SNR for lesions, It was not not statistically significant and MPR TRA CE but CNR came out high. Inspection of post-contrast which is used in a high magnetic field is frequently used images of 3D T1 but, since the signal of the contrast medium and the blood flow is included, this method can be diagnostic accuracy is reduced, it is believed that when used in combination with Post FLAIR, and that can provide video information added to the diagnosis of brain metastases.

• The Journal of Engineering Geology
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• v.30 no.4
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• pp.457-468
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• 2020

Problems arising during pile design works for plant construction, civil and architecture work are mostly come from uncertainty of geotechnical characteristics. In particular, obtaining the N-value measured through the Standard Penetration Test (SPT) is the most important data. However, it is difficult to obtain N-value by drilling investigation throughout the all target area. There are many constraints such as licensing, time, cost, equipment access and residential complaints etc. it is impossible to obtain geotechnical characteristics through drilling investigation within a short bidding period in overseas. The geotechnical characteristics at non-drilling investigation points are usually determined by the engineer's empirical judgment, which can leads to errors in pile design and quantity calculation causing construction delay and cost increase. It would be possible to overcome this problem if N-value could be predicted at the non-drilling investigation points using limited minimum drilling investigation data. This study was conducted to predicted the N-value using an Artificial Neural Network (ANN) which one of the Artificial intelligence (AI) method. An Artificial Neural Network treats a limited amount of geotechnical characteristics as a biological logic process, providing more reliable results for input variables. The purpose of this study is to predict N-value at the non-drilling investigation points through patterns which is studied by multi-layer perceptron and error back-propagation algorithms using the minimum geotechnical data. It has been reviewed the reliability of the values that predicted by AI method compared to the measured values, and we were able to confirm the high reliability as a result. To solving geotechnical uncertainty, we will perform sensitivity analysis of input variables to increase learning effect in next steps and it may need some technical update of program. We hope that our study will be helpful to design works in the future.

• Journal of Korea Port Economic Association
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• v.37 no.4
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• pp.161-173
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• 2021

The shipping industry plummeted and was depressed due to the global economic crisis caused by the bankruptcy of Lehman Brothers in the US in 2008. In 2020, the shipping market also suffered from a collapse in the unstable global economic situation due to the COVID-19 pandemic, but unexpectedly, it changed to an upward trend from the end of 2020, and in 2021, it exceeded the market of the boom period of 2008. According to the Clarksons report published in May 2021, the decrease in cargo volume due to the COVID-19 pandemic in 2020 has returned to the pre-corona level by the end of 2020, and the tramper bulk carrier capacity of 103~104% of the Panamax has been in the ports due to congestion. Earnings across the bulker segments have risen to ten-year highs in recent months. In this study, as factors affecting BDI, the capacity and congestion ratio of Cape and Panamax ships on the supply side, iron ore and coal seaborne tonnge on the demand side and Granger causality test, IRF(Impulse Response Function) and FEVD(Forecast Error Variance Decomposition) were performed using VAR model to analyze the impact on BDI by congestion caused by strengthen quarantine at the port due to the COVID-19 pandemic and the loading and discharging operation delay due to the infection of the stevedore, etc and to predict the shipping market after the pandemic. As a result of the Granger causality test of variables and BDI using time series data from January 2016 to July 2021, causality was found in the Fleet and Congestion variables, and as a result of the Impulse Response Function, Congestion variable was found to have significant at both upper and lower limit of the confidence interval. As a result of the Forecast Error Variance Decomposition, Congestion variable showed an explanatory power upto 25% for the change in BDI. If the congestion in ports decreases after With Corona, it is expected that there is down-risk in the shipping market. The COVID-19 pandemic occurred not from economic factors but from an ecological factor by the pandemic is different from the past economic crisis. It is necessary to analyze from a different point of view than the past economic crisis. This study has meaningful to analyze the causality and explanatory power of Congestion factor by pandemic.

• The Korean Journal of Nuclear Medicine Technology
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• v.14 no.2
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• pp.33-37
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• 2010

Purpose: In the early stage of using PET/CT, it was used to damper revision but recently shows that CT with MDCT is commonly used and works well for an anatomical diagnosis. This hospital makes the accuracy and convenience more higher in the diagnosis and evaluate of coronary heart disease through concurrently running myocardial perfusion SPECT examination, myocardial PET examination with FDG, and CT coronary artery CT angiography(coronary CTA) used PET/CT with 64-slice. This report shows protocol and image based on results from about 400 coronary heart disease examinations since having 64 channels PET/CT in July 2007. Materials and Methods: An Equipment for this examination is 64-slice CT and Discovery VCT (DVCT) that is consisted of PET with BGO ($Bi_4Ge_3O_{12}$) scintillation crystal by GE health care. First myocardial perfusion SPECT with pharmacologic stress test to reduce waiting time of a patient and get a quick diagnosis and evaluation, and right after it, myocardial FDG PET examination and coronary CTA run without a break. One-stop evaluation protocol of ischemic heart disease is as follows. 1)Myocardial perfusion SPECT with pharmacologic stress: A patient is injected with $^{99m}Tc$-MIBI 10 mCi and does not have any fatty food for myocardial PET examination and drink natural water with ursodeoxcholic acid 100 mg and we get SPECT image in an hour. 2)Myocardial FDG PET: To reduce blood fatty content and to increase uptake of FDG, we used creative oral glucose load using insulin and Acipimox to according to blood acid content. A patient is injected with $^{18}F$-FDG 5 mCi for reduction of his radiation exposure and we get a gated image an hour later and get delay image when we need. 3) Coronary CTA: The most important point is to control heart rate and to get cooperation of patient's breath. In order to reduce a heart rate of him or her below 65 beats, let him or her take beta blocker 50 mg ~ 200 mg after a consultation with a doctor about it and have breath-practices then have the examination. Right before the examination, we spray isosorbide dinitrate 3 to 5 times to lower tension of bessel wall and to extension a blood wall of a patient. It makes to get better the shape of an anatomy. At filming, a patient is injected CT contrast with high pressure and have enough practices before the examination in order to have no problem. For reduction of his radiation exposure, we have to do ECG-triggered X-ray tube modulation exposure. Results: We evaluate coronary artery stenosis through coronary CTA and study correlation (culprit vessel check) of a decline between stenosis and perfusion from the myocardial perfusion SPECT with pharmacologic stress, coronary CTA, and can check viability of infarction or hibernating myocardium by FDG PET. Conclusion: The examination makes us to set up a direction of remedy (drug treatment, PCI, CABG) because we can estimate of effect from remedy, lesion site and severity. In addition, we have an advantage that it takes just 3 hours and one-stop in that all of process of examinations run in succession and at the same time. Therefore it shows that the method is useful in one stop evaluation of ischemic heart disease.

• Proceedings of the Safety Management and Science Conference
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• 2004.11a
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• pp.355-380
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• 2004

I test the hypothesis that the gradual diffusion of information across asset markets leads to cross-asset return predictability in Korea. Using thirty-six industry portfolios and the broad market index as our test assets, I establish several key results. First, a number of industries such as semiconductor, electronics, metal, and petroleum lead the stock market by up to one month. In contrast, the market, which is widely followed, only leads a few industries. Importantly, an industry's ability to lead the market is correlated with its propensity to forecast various indicators of economic activity such as industrial production growth. Consistent with our hypothesis, these findings indicate that the market reacts with a delay to information in industry returns about its fundamentals because information diffuses only gradually across asset markets. Traditional theories of asset pricing assume that investors have unlimited information-processing capacity. However, this assumption does not hold for many traders, even the most sophisticated ones. Many economists recognize that investors are better characterized as being only boundedly rational(see Shiller(2000), Sims(2201)). Even from casual observation, few traders can pay attention to all sources of information much less understand their impact on the prices of assets that they trade. Indeed, a large literature in psychology documents the extent to which even attention is a precious cognitive resource(see, eg., Kahneman(1973), Nisbett and Ross(1980), Fiske and Taylor(1991)). A number of papers have explored the implications of limited information- processing capacity for asset prices. I will review this literature in Section II. For instance, Merton(1987) develops a static model of multiple stocks in which investors only have information about a limited number of stocks and only trade those that they have information about. Related models of limited market participation include brennan(1975) and Allen and Gale(1994). As a result, stocks that are less recognized by investors have a smaller investor base(neglected stocks) and trade at a greater discount because of limited risk sharing. More recently, Hong and Stein(1999) develop a dynamic model of a single asset in which information gradually diffuses across the investment public and investors are unable to perform the rational expectations trick of extracting information from prices. Hong and Stein(1999). My hypothesis is that the gradual diffusion of information across asset markets leads to cross-asset return predictability. This hypothesis relies on two key assumptions. The first is that valuable information that originates in one asset reaches investors in other markets only with a lag, i.e. news travels slowly across markets. The second assumption is that because of limited information-processing capacity, many (though not necessarily all) investors may not pay attention or be able to extract the information from the asset prices of markets that they do not participate in. These two assumptions taken together leads to cross-asset return predictability. My hypothesis would appear to be a very plausible one for a few reasons. To begin with, as pointed out by Merton(1987) and the subsequent literature on segmented markets and limited market participation, few investors trade all assets. Put another way, limited participation is a pervasive feature of financial markets. Indeed, even among equity money managers, there is specialization along industries such as sector or market timing funds. Some reasons for this limited market participation include tax, regulatory or liquidity constraints. More plausibly, investors have to specialize because they have their hands full trying to understand the markets that they do participate in

• Investigative Magnetic Resonance Imaging
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• v.22 no.1
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• pp.1-9
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• 2018

Purpose: This study was designed to optimize the flip angle (FA) and scan timing of the hepatobiliary phase (HBP) using the 3D T1-weighted, gradient-echo (GRE) imaging with controlled aliasing in parallel imaging results in higher acceleration (CAIPIRINHA) technique on gadoxetic acid-enhanced 3T liver MR imaging. Materials and Methods: Sixty-two patients who underwent gadoxetic acid-enhanced 3T liver MR imaging were included in this study. Four 3D T1-weighted GRE imaging studies using the CAIPIRINHA technique and FAs of $9^{\circ}$ and $13^{\circ}$ were acquired during HBP at 15 and 20 min after intravenous injection of gadoxetic acid. Two abdominal radiologists, who were blinded to the FA and the timing of image acquisition, assessed the sharpness of liver edge, hepatic vessel clarity, lesion conspicuity, artifact severity, and overall image quality using a five-point scale. Quantitative analysis was performed by another radiologist to estimate the relative liver enhancement (RLE) and the signal-to-noise ratio (SNR). Statistical analyses were performed using the Wilcoxon signed rank test and one-way analysis of variance. Results: The scores of the HBP with an FA of $13^{\circ}$ during the same delayed time were significantly higher than those of the HBP with an FA of $9^{\circ}$ in all the assessment items (P < 0.01). In terms of the delay time, images at the same FA obtained with a 20-min-HBP showed better quality than those obtained with a 15-min-HBP. There was no significant difference in qualitative scores between the 20-min-HBP and the 15-min-HBP images in the non-liver cirrhosis (LC) group except for the hepatic vessel clarity score with $9^{\circ}$ FA. In the quantitative analysis, a statistically significant difference was found in the degree of RLE in the four HBP images (P = 0.012). However, in the subgroup analysis, no significant difference in RLE was found in the four HBP images in either the LC or the non-LC groups. The SNR did not differ significantly in the four HBP images. In the subgroup analysis, 20-min-HBP imaging with a $13^{\circ}$ FA showed the highest SNR value in the LC-group, whereas 15-min-HBP imaging with a $13^{\circ}$ FA showed the best value of SNR in the non-LC group. Conclusion: The use of a moderately high FA improves the image quality and lesion conspicuity on 3D, T1-weighted GRE imaging using the CAIPIRINHA technique on gadoxetic acid, 3T liver MR imaging. In patients with normal liver function, the 15-min-HBP with a $13^{\circ}$ FA represents a feasible option without a significant decrease in image quality.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.3 no.4
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• pp.89-116
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• 2008

RFID (Radio Frequency Identification) is regarded as a core technology of ubiquitous computing. Although it has some technical limitations such as technological standardization of RFID tags as well as economical limitations, many companies around the world have already accepted RFID to improve their management efficiency. In this regard, this study is to meet with results that the adoption of RFID technology willbring opportunities that companies' operational process are improved and customer satisfaction is highly strengthened. This research focuses on providing more understanding for building RFID marketing strategy to suppliers who want to sell their RFID products to customers through analyzing purchasing process. The findings are as follows; First, the study shows that buying center members usually take product reliability and precision of technical specification in the case of new-task buying situation while they put their first purchasing priority on prices in the straight rebuy. Second, the finding presents that in new-task buying situation and the straight rebuy purchasing personnel get information about new products through product performance test, organizational engineers, opinions from other companies' purchasing personnel, and checking out samples. Third, this research demonstrates when it comes to purchasing risk in their first purchasing, the persons who are in charge of material purchasing are inclined to be aware of the risk most in technical problems, followed by financial problems and time delay problems in order. And in addition to those risks are mentioned above, once-again-purchasers take the risk like an opportunity loss for better products into consideration. Fourth, the study shows that the role of concerning departments makes no difference in each purchasing stage. Accordingly marketers need to beef up the differentiated strategy to persuade their customers Fifth, the findings of this study demonstrate that purchasing decision making is much influenced by the final users. So suppliers are supposed to perform the most active marketing strategy at the first stage of purchasing through various resources. Finally, the study presents that the suppliers who will have had close relationships with their customers need to give consistent information to them so that their customers can have lower motive in purchasing products from competitors.

• 한국벤처창업학회:학술대회논문집
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• 2008.11a
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• pp.257-282
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• 2008

RFID (Radio Frequency Identification) is regarded as a core technology of ubiquitous computing. Although it has some technical limitations such as technological standardization of RFID tags as well as economical limitations, many companies around the world have already accepted RFID to improve their management efficiency. In this regard, this study is to meet with results that the adoption of RFID technology willbring opportunities that companies' operational process are improved and customer satisfaction is highly strengthened. This research focuses on providing more understanding for building RFID marketing strategy to suppliers who want to sell their RFID products to customers through analyzing purchasing process. The findings are as follows; First, the study shows that buying center members usually take product reliability and precision of technical specification in the case of new-task buying situation while they put their first purchasing priority on prices in the straight rebuy. Second, the finding presents that in new-task buying situation and the straight rebuy purchasing personnel get information about new products through product performance test, organizational engineers, opinions from other companies' purchasing personnel, and checking out samples. Third, this research demonstrates when it comes to purchasing risk in their first purchasing, the persons who are in charge of material purchasing are inclined to be aware of the risk most in technical problems, followed by financial problems and time delay problems in order. And in addition to those risks are mentioned above, once-again-purchasers take the risk like an opportunity loss for better products into consideration. Fourth, the study shows that the role of concerning departments makes no difference in each purchasing stage. Accordingly marketers need to beef up the differentiated strategy to persuade their customers. Fifth, the findings of this study demonstrate that purchasing decision making is much influenced by the final users. So suppliers are supposed to perform the most active marketing strategy at the first stage of purchasing through various resources. Finally, the study presents that the suppliers who will have had close relationships with their customers need to give consistent information to them so that their customers can have lower motive in purchasing products from competitors.

• Korean Journal of Environmental Biology
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• v.21 no.1
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• pp.72-76
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• 2003

We investigated the effects of molting-hormone insecticide tebufenozide on fourth larvae of the midge C. flaviplumuon in growth development from fourth-instar to adult. Fourth-instar larvae were exposed test concentrations were chosen control, 10 $\mu\textrm{g}$$L^{-1}$, 30 $\mu\textrm{g}$$L^{-1}$, 60 $\mu\textrm{g}$$L^{-1}$ and 100$\mu\textrm{g}$$L^{-1}$. In control and 10 $\mu\textrm{g}$$L^{-1}$, 10~20% individuals succeed adults while low emergence rates were observed surplus 30 $\mu\textrm{g}$$L^{-1}$. Death larvae appeared a various day along the concentration. We observed the converged day: control, 10 $\mu\textrm{g}$$L^{-1}$, 30 $\mu\textrm{g}$$L^{-1}$ and 60~100 $\mu\textrm{g}$$L^{-1}$ were day 4 to day 18, day 13 to day 16, day 9 to day 17 and day 9 to day 15, respectively. Therefore we concerned a tendency that exposure concentration was high, death period was short. Also, due to molting hormone disruption, development of midge was postponed relatively low concentration such as 10 $\mu\textrm{g}$$L^{-1}$. The converged days of pupa stage revealed control, 10 $\mu\textrm{g}$$L^{-1}$, 30 $\mu\textrm{g}$$L^{-1}$ and 60~100$\mu\textrm{g}$$L^{-1}$ were day 11~15, day 16~20, day 9~15 and day 5~9, respectively. About 10% individuals grow up the pupa-stage in 60~100 $\mu\textrm{g}$$L^{-1}$ condition. Sex ratio of the emerged adults was not different in this study. Death pupae frequently appeared in day 13~16 in control, day 6~23 in 10 $\mu\textrm{g}$$L^{-1}$, day 13~16 in 30 $\mu\textrm{g}$$L^{-1}$ and day 6~16 in 60~100 $\mu\textrm{g}$$L^{-1}$.

• Clinical and Experimental Pediatrics
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• v.50 no.9
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• pp.868-874
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• 2007

Purpose : We performed this study to investigate the perinatal and developmental features of the patients with congenital myotonic dystrophy (CDM) confirmed by the molecular genetic method and the clinical characteristics of their mother, and to identify the relation between the number of CTG repeats and the clinical severity.Methods : A retrospective review of the medical records and the results of the dystrophia myotonica protein kinase (DMPK) gene test was done for the patients who were confirmed as CDM through gene analysis from January 2001 to September 2006. Results : All of the eight patients (male 2, female 6) showed moderate to severe degree of perinatal distress and feeding difficulty associated with profound hypotonia. Three patients had the history of polyhydramnios and two patients had equinovarus deformity. The developmental milestones were delayed in all patients, which improved gradually with age. All of their mothers demonstrated myotonic symptoms and typical myopathic face. The number of CTG repeats in DMPK gene analysis ranged 1,000-2,083, and there was no significant correlation between the number of CTG repeats and the time of walking alone. Conclusion : All patients with CDM presented with severe hypotonia in perinatal period, and developmental delay thereafter, which were improved with age. All of their mothers manifested myotonic symptoms with typical myopathic face, and the identification of such features greatly contributed to the diagnosis of the patients. The number of CTG repeats had no significant influence on the motor development.