• Communications for Statistical Applications and Methods
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• v.27 no.5
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• pp.569-578
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• 2020

Various graph clustering methods have been introduced to identify communities in social or biological networks. This paper studies the entropy-based and the Markov chain-based methods in clustering the undirected graph. We examine the performance of two clustering methods with conventional methods based on quality measures of clustering. For the real applications, we collect the mathematical subject classification (MSC) codes of research papers from published mathematical databases and construct the weighted code-to-document matrix for applying graph clustering methods. We pursue to group MSC codes into the same cluster if the corresponding MSC codes appear in many papers simultaneously. We compare the MSC clustering results based on the several assessment measures and conclude that the Markov chain-based method is suitable for clustering the MSC codes.

• Proceedings of the Korean Information Science Society Conference
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• 2000.04a
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• pp.451-453
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• 2000

메시지 순서도(Message Sequence Chart,MSC)는 ITU-T에서 국제적인 표준으로 제안되어 주로 전기 통신 교환 시스템과 같은 실시간 시스템을 위한 통신 행위에 대한 개괄적인 표현 방법으로서 널리 사용되어지고 있으며 요구 명세, 인터페이스 명세, 시뮬레이션 및 검정을 위해 사용되어지고 있다. MSC의 장점이라면 표현된 시스템의 행위를 직관적으로 이해할 수 있게 해주는 그래픽 표현을 제공하는 것이다. 의미론 입장에서 보면 MSC는 폴세스 대수 ACP의 변형인 PA$\varepsilon$에 의해 의미를 부여받고 있긴 하지만 이해하기가 난해한 것이 사실이다. 본 논문에서는 MSC의 동작적 의미를 분석하며 ACSR로 변환하여 그 의미를 보다 쉽게 파악하는 방법론에 대해 다룬다.

• International Journal of Safety
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• v.6 no.1
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• pp.7-10
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• 2007

In this paper, we found that modification of the local flexibility (or local stiffness) of the 4 parts on which shock absorbers are mounted in the vehicle body has some influence the level of ride safety and comfort. Multi-body dynamic analysis considering the flexibility of the vehicle body is performed using MSC/ADAMS and MSC/NASTRAN. More concretely speaking, natural frequencies and mode shapes computed by MSC/NASTRAN are used as input data for multi-body dynamic analysis in MSC/ADAMS. It is confirmed that the ride comfort can be improved by appropriately changing the local stiffness of the vehicle body through several simulations using MSC/ADAMS.

• Preventive Nutrition and Food Science
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• v.14 no.2
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• pp.95-101
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• 2009

In this study, we assessed the effects of Se-methylselenocysteine (MSC) pretreatment on the antioxidant system in the pancreas and the development of alloxan-induced diabetes in rats. The rats were treated with MSC at a dose of 0.75 mg/rat/day for 2 weeks. The MSC-treated rats evidenced significantly increased glutathione content, GSH/GSSG ratio, and glutathione peroxidase (GPx) and glutathione reductase (GRd) activities in the pancreas. Diabetes was induced via alloxan injection. The alloxan-diabetic rats evidenced significantly reduced glutathione content and glucose 6-phosphate dehydrogenase (G6PD) activity and increased catalase activity in the pancreas, when measured 3 days after the alloxan injection. 2-week MSC pretreatment was shown to prevent the alloxan-induced hyperglycemia as well as changes in glutathione content, G6PD activity, and catalase activity. The results of this study indicate that the prevention of alloxan-diabetes by MSC pretreatment is associated with its effects on antioxidants in the pancreas, namely, the increase in cellular content and the reduction of glutathione by the facilitation of glutathione recycling induced via increased GPx, GRd, and G6PD activities.

• Proceedings of the KSRS Conference
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• 2002.10a
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• pp.241-241
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• 2002

MSC(Multi-Spectral Camera) is a main payload of KOMPSAT(Korea Multi-Purpose Satellite)-II which will be launched in 2004. MSC will perform his mission with the GSD(Ground Sample Distance) of 1m, swath width of 15km and spectral range of 450nm~900nm at the altitude of 685km. MSC consists of three main subsystems. One is EOS(Electro-Optics Subsystem), another is PMU(Payload Management Unit) and the other is PDTS(Payload Data Transmission Subsystem). There is an SBC(Single Board Computer) in the PW to control all the other units and SBC software performs the interface with spacecraft and control all MSC sub-units. SBC software consists of a lot of tasks and manages them with the time criticalness. All tasks are designed to be scheduled and executed at the predetermined time in order to make sure that the mission of MSC system is achieved successfully. In this paper, the real-time task scheduling of the SBC software will be described and analyzed.

• Proceedings of the KSRS Conference
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• 2004.10a
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• pp.452-455
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• 2004

MSC (Multi-Spectral Camera) system is a remote sensing instrument to obtain high resolution ground image. EOS (Electro-Optic System) for MSC mainly consists of PMA (Primary Mirror Assembly), SMA (Secondary Mirror Assembly), HSTS (High Stability Telescope Structure) and DFPA (Detector Focal Plane Assembly). High performance of EOS makes it possible for MSC system to provide high resolution and high quality ground images. Temperature of the EOS needs to be controlled to be in a specific range in order not to have any thermal distortion which can cause performance degradation. It is controlled by full redundant CPU based electronics. The validity of thermistor readings can be checked because a few thermistors are installed on each control point on EOS. Various kinds of thermal control logics are used to prevent 'Single Point Failure'. Control logic has a few set of database in order not to be corrupted by SEU (Single Event Upset). Even though the thermal control logic is working automatically, it can also be monitored and controlled by ground-station operator. In this paper, various ways of thermal control logic for EOS in MSC will be presented, which include thermal control mode and logic, redundancy design and status monitoring and reporting scheme.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.825-827
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• 2003

Multi-Spectral Camera(MSC) is a payload on the KOMPSAT-2 satellite to perform the earth remote sensing. The instrument images the earth using a push-broom motion with a swath width of 15 km and a ground sample distance (GSD) of 1 m over the entire field of view (FOV) at altitude 685 Km. The instrument is designed to have an on-orbit operation duty cycle of 20% over the mission lifetime of 3 years with the functions of programmable gain/ offset and on-board image data compression/storage. The MSC instrument has one(1) channel for panchromatic imaging and four(4) channel for multi-spectral imaging covering the spectral range from 450nm to 900nm using TDI CCD Focal Plane Array (FPA). In this paper, the architecture and function of MSC hardware including electrical interface and the operation concept which have been established based on the mission requirements are described. And the design and the preparation of MSC system operation are analyzed and discussed.

• Journal of Life Science
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• v.24 no.11
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• pp.1238-1243
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• 2014

Mesenchymal stem cells (MSCs) have been widely used as cellular therapeutic agents. They have their own characteristic stemness, and thus, they can be used in the treatment of many chronic diseases and in anticancer therapy. MSC therapy has many advantages over chemical therapy. MSC therapy is based on self or homogeneous origin; as such, it is expected to be effective in the treatment of various diseases. In addition, microRNAs in particular have been studied for their structure and function, and they are also expected to prove effective for use as therapeutic agents in cancer or chronic diseases. MicroRNAs are largely associated with metabolism and homeostasis. Therefore, over- or under-expression of microRNAs leads to chronic diseases. Conversely, effective control of the expression of specific microRNAs reduces the risk of many chronic diseases. However, there have been no reports thus far on the synergistic effects of MSCs and microRNAs. Therefore, in this study, we examined the relationship between MSCs and microRNAs using placenta-derived MSCs (PDSCs), bone marrow-derived MSCs (BM-MSCs), and fibroblast (WI-38) cells. We studied the expression of some microRNAs in MSCs and compared the expression in each cell line and cell passage. As a result, we found that the expression of microRNA-34a was higher in PDSCs than in BM-MSCs and that the expression of microRNA-27a, 33a, 33b, and 211 was higher in BM-MSCs than in PDSCs. Therefore, we expect that each MSC line will be used as cell therapy, considering its expressed functional microRNA.

• Development and Reproduction
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• v.13 no.4
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• pp.227-237
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• 2009

Recently, adipose mesenchymal stem cells (AdMSC) that are similar to bone marrow MSC and blood derived MSC are thought to be another source for stem cell therapy. However, the diseases that can be applied for stem cells therapy are age-dependent degenerative diseases. Accordingly, the present study investigated the growth and differentiation potential to neural cells of human AdMSC (hAdMSC) obtained from aged thirty, forty and fifty. The growth of cells and cell viability were measured by passage and neural differentiation of hAdMSC was induced in neural differentiation condition for 10 days. Our results demonstrated that cell number, viability and morphology were not different from hAdMSC by age and passage. Immunofluorescence analysis of neural cell marker (TuJ1, NSE, Sox2, GFAP or MAP2) demonstrated no significant differences in neural cell differentiation by age and passage. As the number of passage was increased, the mRNA level of MAP2 and Sox2 was decreased in hAdMSC from age of 50 compared to hAdMSC from age of 30. In conclusion, the present study demonstrated that ability of neural cell differentiation of hAdMSC was maintained with ages, suggesting that autologous stem cells from aged people can be applied for stem cell therapy with age-dependent neural disease with the same stem cell quality and ability as stem cell derived from young age.

• Korean Journal of Clinical Laboratory Science
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• v.52 no.4
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• pp.417-424
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• 2020

This study aimed to explore the effects of brain-derived neurotrophic factor (BDNF), produced by engineered immortalized mesenchymal stem cells (imMSC), on lower urinary tract symptoms (LUTS) in a rat model with neurogenic bladder (NB). Forty-eight Sprague-Dawley (SD) rats were randomly divided into the following groups: Sham control, LUTS, LUTS+imMSC (treated with immortalized MSC), and LUTS+BDNF-eMSC (treated with BDNF-expressing MSC) groups. LUTS was induced by a crush injury to the major pelvic ganglion (MPG). Bladder function was tested under anesthesia, and bladder tissue strips were collected thereafter for contractility test and western blot analysis. Western blot results showed that the expression of both Angiopoietin 1 (Ang 1) and platelet-derived growth factor (PDGF) increased with MSC injection. The effect of treatment with BDNF-eMSC on LUTS was also evaluated, and the results were found to be better than those with imMSC (P<0.05). BDNF-eMSC prevented fibrosis in the bladder tissue and significantly reduced caspase-3 levels. In conclusion, high expression of BDNF in vivo resulted in recovery of bladder function and contractility, along with the inhibition of apoptosis in a rat model.