• Journal of Chest Surgery
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• v.39 no.7 s.264
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• pp.511-519
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• 2006

Background: Loss of cardiomyocytes in the myocardial infarction leads to regional contractile dysfunction, and necrotized cardiomyocytes in infracted ventricular tissues are progressively replaced by fibroblasts forming scar tissue. Although cardiomyoplasty, or implantation of ventricular assist device or artificial heart was tried in refractory heart failure, the cardiac transplantation was the only therapeutic modality because these other therapeutic strategies were not permanent. Cell transplantation is tried instead of cardiac transplantation, especially bone marrow is the most popular donated organ. But because bone marrow aspiration procedure is invasive and painful, and it had the fewer amounts of cellular population, the adipose tissue is recommended for harvesting of mesenchymal stem cells. Material and Method: After adipose tissues were extracted from abdominal subcutaneous adipose tissue and intra-abdominal adipose tissue individually, the cellular components were obtained by same method. These cellular components were tried to transformation with the various titers of 5-azacytidine to descript the appropriate concentration of 5-azacytidine and possibility of transformation ability of adipose tissue. Group 1 is abdominal subcutaneous adipose tissue and Group 2 is intra-abdominal adipose tissue-retroperitoneal adipose tissue and omentum. Cellular components were extracted by collagenase and $NH_4Cl$ et al, and these components were cultured by non-induction media - DMEM media containing 10% FBS and inducted by none, $3{\mu}mol/L,\;6{\mu}mol/L,\;and\;9{\mu}mol/L$ 5-azacytidine after the 1st and 2nd subculture. After 4 weeks incubation, tile cell blocks were made, immunostaining was done with the antibodies of CD34, heavy myosin chain, troponin T, and SMA. Result: Immunostaining of the transformed cells for troponin T was positive in the $6{\mu}mol/L\;&\;9{\mu}mol/L$ 5-azacytidine of Group 1 & 2, but CD34 and heavy myosin chain antibodies were negative and SMA antibody was positive in the $3{\mu}mol/L\;&\;6{\mu}mol/L$ 5-azacytidne of Group 2. Conclusion: These observations confirm that adult mesenchymal stem cells isolated from the abdominal subcutaneous adipose tissues and intra-abdominal adipose tissues can be chemically transformed into cardiomyocytes. This can potentially be a source of autologous cells for myocardial repair.

• The Korean Journal of Nuclear Medicine
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• v.38 no.6
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• pp.486-491
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• 2004

Purpose: factor analysis and independent component analysis (ICA) has been used for handling dynamic image sequences. Theoretical advantages of a newly suggested ICA method, ensemble ICA, leaded us to consider applying this method to the analysis of dynamic myocardial $H_2^{15}O$ PET data. In this study, we quantified patients' blood flow using the ensemble ICA method. Materials and Methods: Twenty subjects underwent $H_2^{15}O$ PET scans using ECAT EXACT 47 scanner and myocardial perfusion SPECT using Vertex scanner. After transmission scanning, dynamic emission scans were initiated simultaneously with the injection of $555{\sim}740$ MBq $H_2^{15}O$. Hidden independent components can be extracted from the observed mixed data (PET image) by means of ICA algorithms. Ensemble learning is a variational Bayesian method that provides an analytical approximation to the parameter posterior using a tractable distribution. Variational approximation forms a lower bound on the ensemble likelihood and the maximization of the lower bound is achieved through minimizing the Kullback-Leibler divergence between the true posterior and the variational posterior. In this study, posterior pdf was approximated by a rectified Gaussian distribution to incorporate non-negativity constraint, which is suitable to dynamic images in nuclear medicine. Blood flow was measured in 9 regions - apex, four areas in mid wall, and four areas in base wall. Myocardial perfusion SPECT score and angiography results were compared with the regional blood flow. Results: Major cardiac components were separated successfully by the ensemble ICA method and blood flow could be estimated in 15 among 20 patients. Mean myocardial blood flow was $1.2{\pm}0.40$ ml/min/g in rest, $1.85{\pm}1.12$ ml/min/g in stress state. Blood flow values obtained by an operator in two different occasion were highly correlated (r=0.99). In myocardium component image, the image contrast between left ventricle and myocardium was 1:2.7 in average. Perfusion reserve was significantly different between the regions with and without stenosis detected by the coronary angiography (P<0.01). In 66 segment with stenosis confirmed by angiography, the segments with reversible perfusion decrease in perfusion SPECT showed lower perfusion reserve values in $H_2^{15}O$ PET. Conclusions: Myocardial blood flow could be estimated using an ICA method with ensemble learning. We suggest that the ensemble ICA incorporating non-negative constraint is a feasible method to handle dynamic image sequence obtained by the nuclear medicine techniques.

• Journal of Intelligence and Information Systems
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• v.26 no.4
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• pp.87-109
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• 2020

Currently, thanks to the major stride made in developing wired and wireless communication technology, a variety of IT services are available on land. This trend is leading to an increasing demand for IT services to vessels on the water as well. And it is expected that the request for various IT services such as two-way digital data transmission, Web, APP, etc. is on the rise to the extent that they are available on land. However, while a high-speed information communication network is easily accessible on land because it is based upon a fixed infrastructure like an AP and a base station, it is not the case on the water. As a result, a radio communication network-based voice communication service is usually used at sea. To solve this problem, an additional frequency for digital data exchange was allocated, and a ship ad-hoc network (SANET) was proposed that can be utilized by using this frequency. Instead of satellite communication that costs a lot in installation and usage, SANET was developed to provide various IT services to ships based on IP in the sea. Connectivity between land base stations and ships is important in the SANET. To have this connection, a ship must be a member of the network with its IP address assigned. This paper proposes a SANET-CC protocol that allows ships to be assigned their own IP address. SANET-CC propagates several non-overlapping IP addresses through the entire network from land base stations to ships in the form of the tree. Ships allocate their own IP addresses through the exchange of simple requests and response messages with land base stations or M-ships that can allocate IP addresses. Therefore, SANET-CC can eliminate the IP collision prevention (Duplicate Address Detection) process and the process of network separation or integration caused by the movement of the ship. Various simulations were performed to verify the applicability of this protocol to SANET. The outcome of such simulations shows us the following. First, using SANET-CC, about 91% of the ships in the network were able to receive IP addresses under any circumstances. It is 6% higher than the existing studies. And it suggests that if variables are adjusted to each port's environment, it may show further improved results. Second, this work shows us that it takes all vessels an average of 10 seconds to receive IP addresses regardless of conditions. It represents a 50% decrease in time compared to the average of 20 seconds in the previous study. Also Besides, taking it into account that when existing studies were on 50 to 200 vessels, this study on 100 to 400 vessels, the efficiency can be much higher. Third, existing studies have not been able to derive optimal values according to variables. This is because it does not have a consistent pattern depending on the variable. This means that optimal variables values cannot be set for each port under diverse environments. This paper, however, shows us that the result values from the variables exhibit a consistent pattern. This is significant in that it can be applied to each port by adjusting the variable values. It was also confirmed that regardless of the number of ships, the IP allocation ratio was the most efficient at about 96 percent if the waiting time after the IP request was 75ms, and that the tree structure could maintain a stable network configuration when the number of IPs was over 30000. Fourth, this study can be used to design a network for supporting intelligent maritime control systems and services offshore, instead of satellite communication. And if LTE-M is set up, it is possible to use it for various intelligent services.