• The Korean Journal of Nuclear Medicine Technology
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• v.16 no.1
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• pp.86-90
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• 2012

Purpose: Quantification of myocardial blood flow (MBF) using dynamic PET imaging has the potential to assess coronary artery disease. Rb-82 plays a key role in the clinical assessment of myocardial perfusion using PET. However, MBF could be overestimated due to the underestimation of left ventricular input function in the beginning of the acquisition when the scanner has non-linearity between count rate and activity concentration due to the scanner dead-time. Therefore, in this study, we evaluated the count rate linearity as a function of the activity concentration in PET data acquired in list mode. Materials & methods: A cylindrical phantom (diameter, 12 cm length, 10.5 cm) filled with 296 MBq F-18 solution and 800 mL of water was used to estimate the linearity of the Biograph 40 True Point PET/CT scanner. PET data was acquired with 10 min per frame of 1 bed duration in list mode for different activity concentration levels in 7 half-lives. The images were reconstructed by OSEM and FBP algorithms. Prompt, net true and random counts of PET data according to the activity concentration were measured. Total and background counts were measured by drawing ROI on the phantom images and linearity was measured using background correction. Results: The prompt count rates in list mode were linearly increased proportionally to the activity concentration. At a low activity concentration (<30 kBq/mL), the prompt net true and random count rates were increased with the activity concentration. At a high activity concentration (>30 kBq/mL), the increasing rate of the prompt net true rates was slightly decreased while the increasing rate of random counts was increased. There was no difference in the image intensity linearity between OSEM and FBP algorithms. Conclusion: The Biograph 40 True Point PET/CT scanner showed good linearity of count rate even at a high activity concentration (~370 kBq/mL).The result indicates that the scanner is useful for the quantitative analysis of data in heart dynamic studies using Rb-82, N-13, O-15 and F-18.

• Environmental and Resource Economics Review
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• v.22 no.4
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• pp.817-841
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• 2013

The purpose of this study is to examine feasibility of the 'Master Plan of 2013 Slow Food Expo(2013 AsiO Gusto), Korea' and to analyze the following economic effect. To this end, we used existing data and statistics, and estimated the demand by means of survey for people's traveling and questionnaires for ordinary Koreans. For examining financial feasibility for hosting the Expo, BC ratio (Benefit-Cost Ratio) and NPV (Net Present Value) was applied. For estimating the economic effect following the Expo, the effect on all over the country and the Gyeong-gi province was analyzed, using the MRIO (Model of Regional Input-Output). Specifically, with the net effect of Expo, the economic feasibility test shows 1.04~2.15 BC ratio with 10% free admission, and 1.02~2.27 BC ratio in Finance analysis. Furthermore, the Expo feeds through Gyeong-gi (including Nam-yang-ku) regional economies with production induction effect, value-added induction effect, and employment induction effect. The amounts of regional effects are 373.6~738.7 billion won, 166.2~327.4 billion won, and 1,971~2,009 persons, respectively. Also, the "2013 Slow Food Expo, Korea" was analyzed profitable in general. Residents in Nam-yang-ju expects the Expo to bring vitalities into their hometown. The Expo is highly related to the positive economic effectiveness of Nam-yang-ju.

• Journal of Climate Change Research
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• v.8 no.1
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• pp.21-30
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• 2017

Recently, There has been much discussed about unused space. This space can be used in a variety of ways. Utilizing it as a facility, craft shop, and utilizing renewable energy generation facilities. Especially, in terms of climate change should be supplied renewable energy. Renewable energy needs to be developed in terms of responding to climate change, and the recent Paris agreement is also emphasizing the importance of renewable energy. In particular, renewable energy needs to be widely disseminated. And renewable energy is limited space. In this regard, idle land can provide opportunities for securing new renewable energy generation facilities. The introduction of new and renewable energy facilities in idle space can enhance the self-sufficiency rate of the local community, which is significant in terms of responding to climate. In this study, to investigate the possibility of utilizing a unused space for a photovoltaic power generation facility, we investigated the amount of electricity which could be generated through photovoltaic power generation, and the economic effects, using a RETScreen model. The results showed that 9,738 MWh of power can be generated and that $4,540tCO_2eqcan$ be saved. Regarding the economic effect, the net present value of the facility was shown to be 2,247,389,020 KRW. As the net present value was shown to be positive, we believe that the installation of a photovoltaic power generation facility in an unused space would have a positive economic effect. We found the net present value following the fluctuation of the SMP price to be positive, though there was some variation. However, as the economic efficiency was shown to be low because the net present value in relation to the maintenance costs was negative, we believe that maintenance costs must be taken fully into account when evaluating economic efficiency. In particular, as subsidies can be used to cover maintenance costs which must be factored into photovoltaic power generation, we believe that photovoltaic power generation can have an economic effect. Because spaces not currently in use can have a positive economic effect as renewable energy power generation facilities, and can also contribute to the reduction of greenhouse gas emissions, unused spaces are thought to greatly help local governments to cope with climate change as well as reinforcing their related capabilities. We believe our study will help local governments with decisions relating to unused real estate utilization in the future.

• Korean small business review
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• v.42 no.3
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• pp.123-144
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• 2020

This study attempt to use secondary data from KIS-Value to understand how rapid globalization strategy affects BGF's performance defined five categories such as sales volume, return on investment, net profit per employee, increase in sales, and increase in net profit per employee. In particular, this research defines the BGF based on the export ratio within five years after the establishment and classifies BGF into three levels according to 25%, 50%, and 75% concentration of exports. The main results of this study were first, the rapid internationalization strategy was proven to have a sales effect in the short and long term, and in particular, the short term effect was more significantly compared to the long term effect. However, the impact on the return on investment(ROI) of BGF was found that the more stringent the BGF level, the more short-term effect on ROI, but the longer-term effect was diluted according to time. Third, the sales growth rate is significant in the short-term depending on the BGF level, but do not have long-term effects same as ROI. On the other hand, the growth rate of net profit has shown that the BGF strategy has a negative (-) effect over the long term. In particular, the higher the BGF level, the greater the negative impact on the increase in net profit.

• Journal of Internet Computing and Services
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• v.21 no.3
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• pp.103-111
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• 2020

Liver cancer is the most fatal cancer that occurs worldwide. In order to diagnose liver cancer, the patient's physical condition was checked by using a CT technique using radiation. Segmentation was needed to diagnose the liver on the patient's abdominal CT scan, which the radiologists had to do manually, which caused tremendous time and human mistakes. In order to automate, researchers attempted segmentation using image segmentation algorithms in computer vision field, but it was still time-consuming because of the interactive based and the setting value. To reduce time and to get more accurate segmentation, researchers have begun to attempt to segment the liver in CT images using CNNs, which show significant performance in various computer vision fields. The pixel value, or numerical value, of the CT image is called the Hounsfield Unit (HU) value, which is a relative representation of the transmittance of radiation, and usually ranges from about -2000 to 2000. In general, deep learning researchers reduce or limit this range and use it for training to remove noise and focus on the target organ. Here, we observed that the range of HU values was limited in many studies but different in various liver segmentation studies, and assumed that performance could vary depending on the HU range. In this paper, we propose the possibility of considering HU value range as a hyper parameter. U-Net and ResUNet were used to compare and experiment with different HU range limit preprocessing of CHAOS dataset under limited conditions. As a result, it was confirmed that the results are different depending on the HU range. This proves that the range limiting the HU value itself can be a hyper parameter, which means that there are HU ranges that can provide optimal performance for various models.

• Korean Journal of Radiology
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• v.20 no.8
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• pp.1275-1284
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• 2019

Objective: To develop algorithms using convolutional neural networks (CNNs) for automatic segmentation of acute ischemic lesions on diffusion-weighted imaging (DWI) and compare them with conventional algorithms, including a thresholding-based segmentation. Materials and Methods: Between September 2005 and August 2015, 429 patients presenting with acute cerebral ischemia (training:validation:test set = 246:89:94) were retrospectively enrolled in this study, which was performed under Institutional Review Board approval. Ground truth segmentations for acute ischemic lesions on DWI were manually drawn under the consensus of two expert radiologists. CNN algorithms were developed using two-dimensional U-Net with squeeze-and-excitation blocks (U-Net) and a DenseNet with squeeze-and-excitation blocks (DenseNet) with squeeze-and-excitation operations for automatic segmentation of acute ischemic lesions on DWI. The CNN algorithms were compared with conventional algorithms based on DWI and the apparent diffusion coefficient (ADC) signal intensity. The performances of the algorithms were assessed using the Dice index with 5-fold cross-validation. The Dice indices were analyzed according to infarct volumes (< 10 mL, ≥ 10 mL), number of infarcts (≤ 5, 6-10, ≥ 11), and b-value of 1000 (b1000) signal intensities (< 50, 50-100, > 100), time intervals to DWI, and DWI protocols. Results: The CNN algorithms were significantly superior to conventional algorithms (p < 0.001). Dice indices for the CNN algorithms were 0.85 for U-Net and DenseNet and 0.86 for an ensemble of U-Net and DenseNet, while the indices were 0.58 for ADC-b1000 and b1000-ADC and 0.52 for the commercial ADC algorithm. The Dice indices for small and large lesions, respectively, were 0.81 and 0.88 with U-Net, 0.80 and 0.88 with DenseNet, and 0.82 and 0.89 with the ensemble of U-Net and DenseNet. The CNN algorithms showed significant differences in Dice indices according to infarct volumes (p < 0.001). Conclusion: The CNN algorithm for automatic segmentation of acute ischemic lesions on DWI achieved Dice indices greater than or equal to 0.85 and showed superior performance to conventional algorithms.

• Journal of Family Resource Management and Policy Review
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• v.19 no.1
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• pp.73-92
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• 2015

This study is to review the policy objective of the spread of family value in 2nd Family Policy 2011-2015. The spread of family value is newly adapted sphere in 2nd Family Policy. But this policy objective is not clear, diverse or comprehensive. So, this study attempts to examine two questions: what is the family value in healthy family policy? How this objective is reflected to policy services. Because families are shaped by changes in social norm or trend, this study examined the changing demographics of family affect to family value. And the meaning of family value and the viewpoints are clarified. Last, for the extend of this policy objective, this study suggests to reach consensus on future family in Korean society, to emphasize function of family as social safety net.

• Asia pacific journal of information systems
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• v.7 no.1
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• pp.99-111
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• 1997

This paper presents an application of an artificial neural net to the implementation of decision class analysis (DCA), together with the generation of a decision model influence diagram. The diagram is well-known as a good tool for knowledge representation of complex decision problems. Generating influence diagram model is known to in practice require much time and effort, and the resulting model can be generally applicable to only a specific decision problem. In order to reduce the burden of modeling decision problems, the concept of DCA is introduced. DCA treats a set of decision problems having some degree of similarityz as a single unit. We propose a method utilizing a feedforward neural net with supervised learning rule to develop DCA based on influence diagram, which method consists of two phases: Phase l is to search for relevant chance and value nodes of an individual influence diagram from given decision and specific situations and Phase II elicits arcs among the nodes in the diagram. We also examine the results of neural net simulation with an example of a class of decision problems.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.46 no.3
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• pp.265-275
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• 2010

The main purpose of this study is to estimate willingness to pay (WTP) by the general publics, assuming that they pay tax or charge for protecting marine living resources and environment through developing and supplying biodegradable fishing nets. This study employed a contingent valuation method (CVM) which is an econometric method. The survey was conducted by using both double-bounded dichotomous choice and open-ended survey. Tobit model was used for the analysis. The variables included concerns about marine environment and fishing net discarded, sex, age profile, number of family members, educational level and personal disposable income. Annual average WTP per family for the biodegradable fishing net development and supply was estimated at 5,294 won and national WTP amounted to some 84.2 billion won. This includes both of use and non-use value of biodegradable fishing nets.

• The Research Journal of the Costume Culture
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• v.8 no.5
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• pp.707-716
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• 2000

The purpose of this study was to explane the Net generation's characters appearing in the apparel brand naming for them. For this study, first I was trying to explane the New generation characters, second 45 apparel brands were selected by market research and questionaire survey was conducted on 53 the Net generation collage women of age 20 thru 21. Third, the apparel brands were classified into four types according to the characters reflecting in the apparel brand naming : First, the apparel brand type using the figures such as STORM=292513, 1492Miles. Second, the apparel brand type that two or more words are abbreviated into one word. Third, the apparel brand type containing more than one meaning in a brand naming or spelling the words as it pronunciate. Fourth, the apparel brand type using of slang. In conclusion, These types of the apparel brands were related to characters of the New generation, i.e., they who have grown in the advance of digital civilization are skilled in the communication through computer, internet and mobile phone, so that they are familiar with the figures, combined words, or abbreviated words etc. Also, they have individual, sensitivity character and seek after individuality, current fashion. They have also a tendency to accept various the sense of value, while they have a refusing tendency a custom or convention which the older generation has conformited.