• 보건행정학회지
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• 제31권1호
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• pp.125-139
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• 2021

Background: In Korea, the health gap widens due to the number of medical resources and access to medical services between metropolitan and rural. The purpose of this study is to identify the impact of residential migration on medical utilization and accessibility. Methods: This study extracted 528,516 claimed cases in the National Health Insurance Service-Cohort Sample Database from 2006 to 2015. Subjects were classified into two groups by the magnitude of the region, the metropolitan and the rural. The inversed probability weights were calculated for each group. And coefficients of the two-part model were estimated by generalized estimation equation. Results: Those who moved region from metropolitan to rural tend to increase the length of stay and inpatients with ambulatory care sensitive conditions (ACSC) disease. Contrariwise, those who moved areas from rural to metropolitan tend to decrease the total medical cost, the adjusted patient days, the number of outpatients and the number of outpatients and inpatients with ACSC disease. Conclusion: This study identified that between the residents who continued to reside in the region and the migrants, there were significant differences in the medical accessibility, quality of primary care, and unmet medical need.

• 정보처리학회논문지D
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• 제10D권7호
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• pp.1155-1160
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• 2003

본 논문은 분산 서버 환경에서 다양한 업무를 운영하려고 할 때에 발생되는 보안상의 문제를 해결하기 위하여 RBAC(Role Based Access Control) 기법을 이용하여 분산 환경에서 운영 가능한 역할 위임을 위한 확장된 RBAC(Extended RBAC: ERBAC) 모형을 설계하였다. ERBAC는 기본적으로 Sandhu 등이 제안한 RBAC96 모형에 역할 위임부분을 추가하였다. 따라서, 역할을 위임하기 위해 ERBAC를 이용하면 사용자 수준의 역할 위임이 가능하여 업무의 중단 없이 영속성을 보장할 수 있다. 또한 분산 서버의 소스코드 수정 없이 구현 가능하고, 이식성이 높으며, 보안 관리가 단순하고 용이하다는 장점을 갖는다.

• East Asian Economic Review
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• 제26권2호
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• pp.143-169
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• 2022

This study investigates the effect of economic factors on immigration using the gravity model of immigration. Cross-sectional regression and panel data analyses are conducted from 2000 to 2019 using the OECD International Migration Database, which consists of 36 destination countries and 201 countries of origin. The Poisson pseudo-maximum-likelihood method, which can effectively correct potential biased estimates caused by zeros in the immigration data, is used for estimation. The results indicate that the economic factors strengthened after the global financial crisis. Additionally, this effect varies depending on the type of immigration (the income level of origin country). The gravity model applied to immigration performs reasonably well, but it is necessary to consider the country-specific and time-varying characteristics.

• Journal of Ginseng Research
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• 제41권3호
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• pp.386-391
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• 2017

Background: Korean Red Ginseng (KRG) is an ethnopharmacological plant that is traditionally used to improve the body's immune functions and ameliorate the symptoms of various diseases. However, the antitumorigenic effects of KRG and its underlying molecular and cellular mechanisms are not fully understood in terms of its individual components. In this study, in vitro and in vivo antitumorigenic activities of KRG were explored in water extract (WE), saponin fraction (SF), and nonsaponin fraction (NSF). Methods: In vitro antitumorigenic activities of WE, SF, and NSF of KRG were investigated in the C6 glioma cell line using cytotoxicity, migration, and proliferation assays. The underlying molecular mechanisms of KRG fractions were determined by examining the signaling cascades of apoptotic cell death by semiquantitative reverse transcriptase polymerase chain reaction and Western blot analysis. The in vivo antitumorigenic activities of WE, SF, and NSF were investigated in a xenograft mouse model. Results: SF induced apoptotic death of C6 glioma cells and suppressed migration and proliferation of C6 glioma cells, whereas WE and NSF neither induced apoptosis nor suppressed migration of C6 glioma cells. SF downregulated the expression of the anti-apoptotic gene B-cell lymphoma-2 (Bcl-2) and upregulated the expression of the pro-apoptotic gene Bcl-2-associated X protein (BAX) in C6 glioma cells but had no effect on the expression of the p53 tumor-suppressor gene. Moreover, SF treatment resulted in activation of caspase-3 as evidenced by increased levels of cleaved caspase-3. Finally, WE, SF, and NSF exhibited in vivo antitumorigenic activities in the xenograft mouse model by suppressing the growth of grafted CT-26 carcinoma cells without decreasing the animal body weight. Conclusion: These results suggest that WE, SF, and NSF of KRG are able to suppress tumor growth via different molecular and cellular mechanisms, including induction of apoptosis and activation of immune cells.

• 한국경제지리학회지
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• 제22권3호
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• pp.351-365
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• 2019

본 연구의 목적은 주요 이동요인별 인구이동 및 인구분포의 시공간적 특징을 분석하고 장래 지역별 인구분포의 변화를 예측하고 전망하는 것이다. 이를 위해 직업, 가족, 주택, 교육 등 주요 이동요인별 거주지 변화로 나타나는 지역별 인구이동의 추이를 파악하고, 장래 지역별 인구 유출입에 의한 인구분포의 변화를 추정하는 예측 시뮬레이션을 진행한다. 분석결과, 거주지를 변경함에 있어 대도시지역과 시 단위 중심의 지리적 이동이 나타나고 있으며 대도시와 시 단위 내에서도 지역별 인구 유출입에 영향을 미치는 주요 이동요인별 구성 비율은 각기 상이하게 나타난다. 또한 이동요인별 시군구별 추이확률과 상태확률을 토대로 6단계-정상 마르코프 연쇄 프로세스를 진행한 결과, 각 이동요인에 따라 장래 시군구별 인구분포의 변화 정도도 차이가 나타날 것으로 추정된다. 본 연구에서 제시하는 방법론과 분석결과는 특히 인구감소로 지방소멸이 우려되는 지역에서 인구의 유입요인은 강화하고 유출요인은 개선하는 지역 맞춤형 인구 및 각종 정책을 계획하고 마련하는데 활용될 수 있다.

• Journal of Microbiology and Biotechnology
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• 제30권3호
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• pp.325-332
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• 2020

Methyl linderone (ML), a cyclo-pentenedione, was isolated from the fruit of Lindera erythrocarpa Makino (family Lauraceae). This plant has well-known anti-inflammatory effects; however, the anti-cancer effects of ML have not yet been reported. Thus, in the present study we investigated the effects of ML on the metastasis of human breast cancer cells. We used 12-O-tetradecanoyl phorbol-13-acetate (TPA)-stimulated MCF-7 cells as the cell model to study the effects of ML on invasion and migration. ML was found to reduce the invasion and migration rate of TPA-stimulated MCF-7 cells. Moreover, it inhibited two metastasis-related factors, matrix metalloproteinase-9 (MMP-9) and interleukin-8 (IL-8), at the mRNA and protein expression levels, in TPA-treated MCF-7 cells. The mechanism by which ML exerted these effects was through the inhibition of translocation of activator protein-1 (AP-1) and signal transducer and activator of transcription-3 (STAT3), mediated via phosphorylation of extracellular signal-regulated kinase (ERK). Taken together, our findings indicated that ML attenuated the TPA-stimulated invasion and migration of MCF-7 cells by suppressing the phosphorylation of ERK and its downstream factors, AP-1 and STAT3. Therefore, ML is a potential agent for the treatment of breast cancer metastasis.

• Corrosion Science and Technology
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• 제6권6호
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• pp.282-285
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• 2007

Smaller size and higher integration of electronic systems make narrower interconnect pitch not only in chip-level but also in package-level. Moreover electronic systems are required to operate in harsher conditions, that is, higher current / voltage, elevated temperature / humidity, and complex chemical contaminants. Under these severe circumstances, electronic components respond to applied voltages by electrochemically ionization of metals and conducting filament forms between anode and cathode across a nonmetallic medium. This phenomenon is called as the electrochemical migration. Many kinds of metal (Cu, Ag, SnPb, Sn etc) using in electronic packages are failed by ECM. Eutectic SnPb which is used in various electronic packaging structures, that is, printed circuit boards, plastic-encapsulated packages, organic display panels, and tape chip carriers, chip-on-films etc. And the material for soldering (eutectic SnPb) using in electronic package easily makes insulation failure by ECM. In real PCB system, not only metals but also many chemical species are included. And these chemical species act as resources of contamination. Model test systems were developed to characterize the migration phenomena without contamination effect. The serpentine-shape pattern was developed for analyzing relationship of applied voltage bias and failure lifetime by the temperature / humidity biased(THB) test.

• 대한암한의학회지
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• 제13권1호
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• pp.13-24
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• 2008

Objective: To evaluate the effects of Bikihaun (BKH) on angiogenesis. Method: We examined the anti-angiogenic effect of BKH in invasion assay model. We performed proliferation assay, migration assay, tube formation assay and Chicken Chorioallantoic Membrane (CAM) assay. Results: In proliferation assay, at lower dose under 125 ${\mu}g/m{\ell}$ anti-angiogenesis effect of the group treated BKH made no difference with the control group. But, at the dose of 250 ${\mu}g/m{\ell}$ or more anti-angiogenesis effect of the group treated BKH showed more effective as compared to the control group. In migration assay, BKH did not affect migration of vascular endothelial cell. In tube formation assay, at lower dose under 100 ${\mu}g/m{\ell}$ showed mild effect of anti-tube formation. But, at the dose of 1000 ${\mu}g/m{\ell}$ showed more effective anti-tube formation. In CAM assay, BKH showed anti-angiogenesis effect at the dose of 10 ${\mu}g/m{\ell}$. Conclusion: BKH has antiangiogenetic properties in vitro.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권11호
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• pp.3916-3936
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• 2014

Smartphone applications like games, image processing, e-commerce and social networking are gaining exponential growth, with the ubiquity of cellular services. This demands increased computational power and storage from mobile devices with a sufficiently high bandwidth for mobile internet service. But mobile nodes are highly constrained in the processing and storage, along with the battery power, which further restrains their dependability. Adopting the unlimited storage and computing power offered by cloud servers, it is possible to overcome and turn these issues into a favorable opportunity for the growth of mobile cloud computing. As the mobile internet data traffic is predicted to grow at the rate of around 65 percent yearly, even advanced services like 3G and 4G for mobile communication will fail to accommodate such exponential growth of data. On the other hand, developers extend popular applications with high end graphics leading to smart phones, manufactured with multicore processors and graphics processing units making them unaffordable. Therefore, to address the need of resource constrained mobile nodes and bandwidth constrained cellular networks, the computations can be migrated to resourceful servers connected to cloud. The server now acts as a bridge that should enable the participating mobile nodes to offload their computations through Wi-Fi directly to the virtualized server. Our proposed model enables an on-demand service offloading with a decision support system that identifies the capabilities of the client's hardware and software resources in judging the requirements for offloading. Further, the node's location, context and security capabilities are estimated to facilitate adaptive migration.

• IMMUNE NETWORK
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• 제6권2호
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• pp.76-85
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• 2006

Background: Chemotaxis is one of the cardinal functions of leukocytes, which enables them to be recruited efficiently to the right place at the right time. Analyzing chemotactic activities is important not only for the study on leukocyte migration but also for many other applications including development of new drugs interfering with the chemotactic process. However, there are many technical limitations in the conventional in vitro chemotaxis assays. Here we applied a new optical assay to investigate chemotactic activities induced in differentiated HL-60 cells. Methods: HL-60 cells were stimulated with 0.8% dimethylformamide (DMF) for 4 days. The cells were analyzed for morphology, flow cytometry as well as chemotactic activities by a time-lapse videomicroscopic assay using a chemotactic microchamber bearing a fibronectin-coated cover slip and an etched silicon chip. Results: Videomicroscopic observation of the real cellular motions in a stable concentration gradient of chemokines demonstrated that HL-60 cells showed chemotaxis to inflammatory chemokines (CCL3, CCL5 and CXCL8) and also a homeostatic chemokine (CXCL12) after DFM-induced differentiation to granulocytic cells. The cells moved randomly at a speed of $6.99{\pm}1.24{\mu}m/min$ (n=100) in the absence of chemokine. Chemokine stimulation induced directional migration of differentiated HL-60 cells, while they still wandered very much and significantly increased the moving speeds. Conclusion: The locomotive patterns of DMF-stimulated HL-60 cells can be analyzed in detail throughout the course of chemotaxis by the use of a time-lapse videomicroscopic assay. DMF-stimulated HL-60 cells may provide a convenient in vitro model for chemotactic studies of neutrophils.