• The Korean Journal of Nuclear Medicine Technology
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• v.15 no.1
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• pp.34-38
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• 2011

Purpose: The SUV is a widely used semi-quantitative index in PET for the estimation of radio-tracer accumulation in VOI. In this study, SUVs from three different PET/CT scanners were assessed, and differences between SUVs were evaluated. Materials and Methods: The PET/CT scanners which were assessed in this study were GEMINI, GEMINI TF 64 (Philips) and Biograph True Point True V 40 (Siemens). The NEMA PET phantom (Data Spectrum Corp., USA) was used to evaluate SUVs. The NEMA PET phantom has6.8 kg weight and three hot inserts. Two different activity distributions for the background and inserts were tested. The activity ratio were 3.7:3.7:7.4:11.1 MBq (1:1:2:3) and 1.85:7.4:9.25:11.1MBq (1:4:5:6) for each of background, insert 1, insert 2 and insert 3. Acquisition time was 2 minutes per bed position and NEMA PET phantom could be covered by two bed positions for all PET/CT scanners. The SUVs from each PET/CT scanner were compared with calculated true value. Results: For both activity ratios, all scanners showed similar results. The differences between each scanner were insignificant. Each scanner showed 91.2%, 85.9% and 87.2% of true SUV for GEMINI, GEMINI TF 64, Biograph True Point TrueV, respectively. Conclusion: For all scanners, SUVs were slightly lower than true value. However, the difference between scanners was insignificant. The SUVs from these scanners would be clinically meaningful if their consistent underestimation is kept in mind.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.4 no.4
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• pp.45-70
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• 2009

This article investigates which types of the strategies announced by the listed firms contribute to enhancing the long-term performance of the companies. Since 2002, Korean Exchange adopted the "faire disclosure policy" which mandates that all publicly traded companies must disclose material information to all investors at the same time. Thanks to the policy, Korean investors can, now, easily access the board's decision on management strategies on the same day the decision is made. If the companies trustfully carry out their announced strategies, we can decide which types of strategies actually enhance or deteriorate the long-term performance, simply by comparing the announced strategies and the firm's performance. The sample companies are confined to 60 firms that became listed in the KOSDAQ market through back-door listing from 2003 to 2005. Using only the newly listed companies, we can avoid the interference on the long-term performance of the strategies pursued before the event date. This often holds true, for many companies radically modify their strategies after the listing. Furthermore, the back-door listing companies serve our purpose better than IPO companies do, because the former tend to have a variety of announcement within a given period of time beginning the listing date. Using these sample companies, this article analyzes the effect on one year buy-and-hold returns and abnormal buy-and-hold returns after the listing of the various types of strategies announced during the same period of time. The results show that those evidences of restructuring such as 'reduction of capital' and 'resignation of incumbent board members', actually contribute to the increase in adjusted long-term stock returns. Those strategies which can be view as evidence of new investment such as 'increase in tangible assets', 'acquisition of other companies', do also helps the stockholders better off. On the contrary, 'increase in bank loans', 'changes of CEO' and 'merger' deteriorate the equity value. The last findings let us to presume that the back-door listing companies appear to use the bank loans for value-reducing activities; the change in CEO is not a sign of restructuring, but rather a sign of failure of the restructuring; another merger carried out after back-door listing itself is also value-reducing activity. This article's findings on reduction of capital, merger and bank loans oppose the results of the former empirical studies which analyze only the short-term effect on stock price. Therefore, more long-term performance studies on public disclosures are in order.

• Nuclear Medicine and Molecular Imaging
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• v.41 no.2
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• pp.172-180
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• 2007

Among the nuclear medicine imaging methods available today, $H_2^{15}O-PET$ is most widely used by cognitive neuroscientists to examine regional brain function via the measurement of regional cerebral blood flow (rCBF). The short half-life of the radioactively labeled probe, $^{15}O$, often allows repeated measures from the same subjects in many different task conditions. $H_2^{15}O-$ PET, however, has technical limitations relative to other methods of functional neuroimaging, e.g., fMRI, including relatively poor time and spatial resolutions, and, frequently, insufficient statistical power for analysis of individual subjects. However, recent technical developments, such as the 3-D acquisition method provide relatively good image quality with a smaller radioactive dosage, which in turn results in more PET scans from each individual, thus providing sufficient statistical power for the analysis of individual subject's data. Furthermore, the noise free scanner environment $H_2^{15}O$ PET, along with discrete acquisition of data for each task condition, are important advantages of PET over other functional imaging methods regarding studying state-dependent changes in brain activity. This review presents both the limitations and advantages of $^{15}O-PET$, and outlines the design of efficient PET protocols, using examples of recent PET studies both in the normal healthy population, and in the clinical population.

• Journal of Biomedical Engineering Research
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• v.33 no.1
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• pp.39-46
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• 2012

Electrical impedance tomography(EIT) can produce functional images with conductivity distributions associated with physiological events such as cardiac and respiratory cycles. EIT has been proposed as a clinical imaging tool for the detection of stroke and breast cancer, pulmonary function monitoring, cardiac imaging and other clinical applications. However EIT still suffers from technical challenges such as the electrode interface, hardware limitations, lack of animal or human trials, and interpretation of conductivity variations in reconstructed images. We improved the KHU Mark2 EIT system by introducing an EIT electrode interface consisting of nano-web fabric electrodes and by adding a synchronized biosignal measurement system for gated conductivity imaging. ECG and respiration signals are collected to analyze the relationship between the changes in conductivity images and cardiac activity or respiration. The biosignal measurement system provides a trigger to the EIT system to commence imaging and the EIT system produces an output trigger. This EIT acquisition time trigger signal will also allow us to operate the EIT system synchronously with other clinical devices. This type of biosignal gated conductivity imaging enables capture of fast cardiac events and may also improve images and the signal-to-noise ratio (SNR) by using signal averaging methods at the same point in cardiac or respiration cycles. As an example we monitored the beat by beat cardiac-related change of conductivity in the EIT images obtained at a common state over multiple respiration cycles. We showed that the gated conductivity imaging method reveals cardiac perfusion changes in the heart region of the EIT images on a canine animal model. These changes appear to have the expected timing relationship to the ECG and ventilator settings that were used to control respiration. As EIT is radiation free and displays high timing resolution its ability to reveal perfusion changes may be of use in intensive care units for continuous monitoring of cardiopulmonary function.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.37 no.6
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• pp.481-489
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• 2019

Change detection, one of the main applications of multi-temporal satellite images, is an indicator that directly reflects changes in human activity. Change detection can be divided into pixel-based change detection and object-based change detection. Although pixel-based change detection is traditional method which is mostly used because of its simple algorithms and relatively easy quantitative analysis, applying this method in VHR (Very High Resolution) images cause misdetection or noise. Because of this, pixel-based change detection is less utilized in VHR images. In addition, the sensor of acquisition or geographical characteristics bring registration noise even if co-registration is conducted. Registration noise is a barrier that reduces accuracy when extracting spatial information for utilizing VHR images. In this study object-based change detection of VHR images was performed considering registration noise. In this case, object-based change detection results were derived considering various pixel-based change detection methods, and the major voting technique was applied in the process with segmentation image. The final object-based change detection result applied by the proposed method was compared its performance with other results through reference data.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.7
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• pp.184-190
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• 2020

In this study, two analyses were conducted in relation to the defense procurement agency. The first was a questionnaire survey conducted by defense business personnel to quantitatively measure the effectiveness of the defense procurement agency's utilization. In the second, the appropriate standard for brokerage fees was developed, the actual work of the defense procurement agency in overseas sales was surveyed, and the brokerage profit of the general product was applied to the defense procurement agency's brokerage profit data. Using the defense procurement agency was 1.07 times more effective than not using it, and the appropriate brokerage fee varied according to the project size. For medium / small projects, 5.1 ~ 8.7% of the total project cost is an appropriate brokerage fee, compared to 1.2 ~ 1.8% for big-scale projects. The government's appropriate brokerage fee is not fixed, but is elastically applied according to the size of the total project cost, and it is appropriate to analyze the characteristics of the project and identify and adjust the required activity cost in advance.

• The Journal of the Korea Contents Association
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• v.17 no.12
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• pp.180-190
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• 2017

This is Kangwon Land casino case due to the damages of betting money, which is likely to affect the contents industry in the future. The reason why the gambler and his family's suit is that why the manager did not control their own access or did not supervise the wagering rules. The provisions of the "Restriction on the amount of money to be paid to the casino" in the Article 14 of the Enforcement Decree of the Act on the Support for the Development of the Abandoned Mine Area are not intended to increase the duty of the casino managers. It is just one of many public regulations imposed. No matter what legislation is made for public interest, it can not be considered equally in the private duty. If so, too much effort will be required to enact or amend the public law and this makes the legislative activity impossible. The Act on the Restriction on Access to the Casino shall be construed accordingly. From the point of view of economic efficiency theory, if we overestimate statutory duties (liability for compensation) excessively, the price goes up on the market, and the volume of transaction decreases drastically. This reduces the economic utility of resources in the society as a whole (total output, foreign currency acquisition amount, etc.).

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.1
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• pp.34-40
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• 2004

The purpose of this study was to measure the changes of regional cerebral blood flow (rCBF) and blood pressure (BP) in rats, following the intravenous injection of Schizandrae fructus water extract. The measurement was continually monitored by laser-doppler flowmeter and pressure tranducer in anesthetized adult Sprague-Dawley rats for 2 hours to 2 hours and a half through the data acquisition system composed of MacLab and Macintosh computer. The result of this experiment was as followed. Schizandrae fructus increased the changes of rCBF in rats significantly. The rCBF of Schizandrae fructus did not change by pretreated propranolol, atropine, L-NNA and indomethacin. But the rCBF of Schizandrae fructus was increased by pretreated methylene blue. Schizandrae fructus decreased the changes of BP, significantly. The BP of Schizandrae fructus did not change by pretreated propranolol, atropine, L-NNA and indomethacin. But the BP of Schizandrae fructus was decreased by pretreated methylene blue. There results indicated that Schizandrae fructus can increase the rCBF and decrease the BP, that is related to guanylyl cyclase activity.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.12 no.6
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• pp.49-63
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• 2017

The purpose of this study is to analyze the effects of the collective characteristics of SMEs on M&A activity on the disclosure effect of mergers and long-term business performance after mergers. From 2000 to 2012, we examine 717 cases of small and medium-sized enterprises (SMEs) using multiple regression analysis and difference analysis. The results of this study are as follows. First, it is confirmed that the effect on the merger announcement effect is the same as the previous study on the Korean capital market listed companies except for the effect of diversification, listing effect, and cross-border effect. In addition, we have found that firms with higher performance in the past have higher excess returns in the disclosure effect of mergers and acquisitions. Second, unlike the previous studies that non-related mergers have a positive effect on long-term operating performance, for the characteristics of SMEs with lower market competitiveness than that of average listed companies, SMEs merging with same industry group companies have a positive effect on long-term operating performance. This study provides a new perspective on the merger and acquisition of SMEs by examining the effects of M&A announcement and long-term performance.

• Investigative Magnetic Resonance Imaging
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• v.16 no.2
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• pp.136-141
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• 2012

Purpose : To investigate the pharmacologic modulation of motor task-dependent physiologic responses by antiplatelet agent, clopidogrel, during hand motor tasks in healthy subjects. Materials and Methods: Ten healthy, right-handed subjects underwent three functional magnetic resonance (fMRI) sessions: one before drug administration, one after high dose drug administration and one after reaching drug steady state. For the motor task fMRI, finger flexion-extension movements were performed. Blood oxygenation level dependent (BOLD) contrast was collected for each subject using a 3.0 T VHi (GE Healthcare, Milwaukee, USA) scanner. $T2^*$-weighted echo planar imaging was used for fMRI acquisition. The fMRI data processing and statistical analyses were carried out using SPM2. Results: Second-level analysis revealed significant increases in the extent of activation in the contralateral motor cortex including primary motor area (M1) after drug administration. The number of activated voxels in motor cortex was 173 without drug administration and the number increased to 1049 for high dose condition and 673 for steady-state condition respectively. However, there was no significant difference in the magnitude of BOLD signal change in terms of peak T value. Conclusion: The current results suggest that cerebral motor activity can be modulated by clopidogrel in healthy subjects and that fMRI is highly senstive to evidence such changes.