• Journal of Preventive Medicine and Public Health
• /
• 제7권1호
• /
• pp.197-201
• /
• 1974

The rapid economic development of Korea since 1960 has also brought a rapid urbanization process, and recently many rural areas have begun to show actual depopulation, in which particularly the young, productive and high educated groups are leaving for cities. More than 70% of migrators go to large cities such as Seoul, Pusan and Taegu. Their main motives for migration are to seek a job in urban areas. The study showed following results; The rate of migration a year was 1% of total population. Regarding the age of migrators belong to between 10-39 years old, especially migrator aged 10-29 years are comprised 87%. The educational level of migrators was a little higher than that of the residents. Considering the sibling order of migrators, the traditional value system for first son seemed to change. Concerning the place of destination, more than 70% of migrators moved to large cities such as Seoul. Pusan and Taegu. The main motivation of migration was to seek a job in urban areas. The occupation at the place of destination were factory workers, employee at company, students, salesmen, farmers and public officials in that order.

• Communications for Statistical Applications and Methods
• /
• 제27권3호
• /
• pp.385-395
• /
• 2020

We present a new maximum likelihood approach to estimate demographic history using genomic data sampled from two populations. A demographic model such as an isolation-with-migration (IM) model explains the genetic divergence of two populations split away from their common ancestral population. The standard probability model for an IM model contains a latent variable called genealogy that represents gene-specific evolutionary paths and links the genetic data to the IM model. Under an IM model, a genealogy consists of two kinds of evolutionary paths of genetic data: vertical inheritance paths (coalescent events) through generations and horizontal paths (migration events) between populations. The computational complexity of the IM model inference is one of the major limitations to analyze genomic data. We propose a fast maximum likelihood approach to estimate IM models from genomic data. The first step analyzes genomic data and maximizes the likelihood of a coalescent tree that contains vertical paths of genealogy. The second step analyzes the estimated coalescent trees and finds the parameter values of an IM model, which maximizes the distribution of the coalescent trees after taking account of possible migration events. We evaluate the performance of the new method by analyses of simulated data and genomic data from two subspecies of common chimpanzees in Africa.

• 한국가시화정보학회지
• /
• 제18권2호
• /
• pp.10-17
• /
• 2020

The curvature of wound boundaries has been identified as a key modulator that determines a type of force responsible for cell migration. While several studies report how certain curvatures of the boundary correlate with the rate at which the wound closes, it remains unclear how these curvatures are spatiotemporally formed to regulate the healing process. We investigated the dynamic changes in the boundary curvatures by visualizing cell migration patterns. Locally, cells at the convex boundary continuously move forward with transmitting kinetic responses behind to the cells away from the boundary, and cells at the concave boundary exhibit dramatic contracting motion, like a purse-string, when they accumulate enough negative curvatures to gain the thrust toward the void. Globally, the dynamics of boundary geometries are controlled by the diffusive flow of cells driven by the density gradient between the wound area and the cell layer.

• Molecules and Cells
• /
• 제41권2호
• /
• pp.103-109
• /
• 2018

Calcium ions are involved in the regulation of diverse cellular processes. Fourteen genes encoding calcium binding proteins have been identified in Dictyostelium. CBP7, one of the 14 CBPs, is composed of 169 amino acids and contains four EF-hand motifs. Here, we investigated the roles of CBP7 in the development and cell migration of Dictyostelium cells and found that high levels of CBP7 exerted a negative effect on cells aggregation during development, possibly by inhibiting chemoattractant-directed cell migration. While cells lacking CBP7 exhibited normal development and chemotaxis similar that of wild-type cells, CBP7 overexpressing cells completely lost their chemotactic abilities to move toward increasing cAMP concentrations. This resulted in inhibition of cellular aggregation, a process required for forming multicellular organisms during development. Low levels of cytosolic free calcium were observed in CBP7 overexpressing cells, which was likely the underlying cause of their lack of chemotaxis. Our results demonstrate that CBP7 plays an important role in cell spreading and cell-substrate adhesion. cbp7 null cells showed decreased cell size and cell-substrate adhesion. The present study contributes to further understanding the role of calcium signaling in regulation of cell migration and development.

• 한국정보통신학회논문지
• /
• 제13권12호
• /
• pp.2707-2718
• /
• 2009

기업들은 개별적이고 다양한 형태의 데이터베이스를 활용하여 업무적으로 발생하는 데이터를 저장, 관리하고 있다. 이렇게 개별적으로 존재하는 데이터 베이스에 저장된 데이터들은 기업에서 특정 서비스목표 달성을 위해서 비즈니스 프로세스라는 것을 통해 접근되고 있고, 데이터에 대한 이주가 빈번하게 이루어지고 있다. 이에 본 논문에서는 SQL Query 기반의 비즈니스 프로세스가 수행되는 과정에서 데이터의 접근 및 통합에서 발생하는 데이터 이주 과정을 XMDR-DAI(eXtended MetaData Registry-Data and Integration)를 이용한 방법을 제시한다.

• 동남아시아연구
• /
• 제24권2호
• /
• pp.207-251
• /
• 2014

This study explores the mobility patterns of Korean Early Study Aborad (ESA, hereafter) students in Singapore through a follow-up longitudinal case study, which was initially conducted about five years before this study. This study takes up transnational migration approach, focusing on family strategies and mobilization, which steered their mobility. Interviews with seven original families as well as 7 families additionally recruited in Singapore in 2012 were collected and analyzed by NVivo 9. In short, this study found that transnational mobility is composed of mobilities at global, regional and local levels. There were four types of mobilities; continuation of stay in Singapore, move from a third county to Singapore, return to Korea, and, what this research calls, fluid mobility. Examining the process of these mobilities shows that we need to consider at least three factors (performance of children's schooling; change of family circumstances; context of reception for both Singapore and Korea) as basic backgrounds. On this basis, the interplay between the context of receptions when aspirations for children's advancement by these transnational families made either facilitate or constrain their mobilities: contexts of Singapore and Korea may play a role of hurdle or trampoline. Also, local context of Singapore largely facilitate mobilities of Korean ESA families at both local and global levels.

• Membrane and Water Treatment
• /
• 제14권2호
• /
• pp.95-106
• /
• 2023

In the developing country like India, groundwater is the main sources for household, irrigation and industrial use. Its contamination poses hydro-geological and environmental concern. The hazardous waste sites such as landfills can lead to contamination of ground water. The contaminants existing at such sites can eventually find ingress down through the soil and into the groundwater in case of leakage. It is necessary to understand the process of migration of pollutants through sub-surface porous medium for avoiding health risks. On this backdrop, the present paper investigates the behavior of pollutants' migration through porous media. The laboratory experiments were carried out on a soil-column model that represents porous media. Two different types of soils (standard sand and red soil) were considered as the media. Further, two different solutes, i.e., non-reactive and reactive, were used. The experimental results are simulated through numerical modeling. The percentage variation in the experimental and numerical results is found to be in the range of 0.75- 11.23 % and 0.84 - 1.26% in case of standard sand and red soil, respectively. While a close agreement is observed in most of the breakthrough curves obtained experimentally and numerically, good agreement is seen in either result in one case.

• Molecules and Cells
• /
• 제39권4호
• /
• pp.345-351
• /
• 2016

Wound healing is a complex physiological process necessitating the coordinated action of various cell types, signals and microRNAs (miRNAs). However, little is known regarding the role of miRNAs in mediating this process. In the present study, we show that let-7c miRNA is decreased in heat-denatured fibroblasts and that inhibiting let-7c expression leads to the increased proliferation and migration of dermal fibroblasts, whereas the overexpression of let-7c exerts an opposite effect. Further investigation has identified heat shock protein 70 as a direct target of let-7c and has demonstrated that the expression of HSP70 in fibroblasts is negatively correlated with let-7c levels. Moreover, down-regulation of let-7c expression is accompanied by up-regulation of Bcl-2 expression and down-regulation of Bax expression, both of which are the downstream genes of HSP70. Notably, the knockdown of HSP70 by HSP70 siRNA apparently abrogates the stimulatory effect of let-7c inhibitor on heat-denatured fibroblasts proliferation and migration. Overall, we have identified let-7c as a key regulator that inhibits fibroblasts proliferation and migration during wound healing.

• Asian Pacific Journal of Cancer Prevention
• /
• 제13권6호
• /
• pp.2437-2444
• /
• 2012

Tumor metastasis remains the principal cause of treatment failure and poor prognosis in patients with colorectal cancer. It is a multistage process which includes proteolysis, motility and migration of cells, proliferation in a new site, and neoangiogenesis. A crucial step in the process of intra- and extra-vasation is the activation of proteolytic enzymes capable of degrading the extracellular matrix (ECM). In this stage, urokinase plasminogen activator receptor (uPAR) and matrix metalloproteinases (MMPs) are necessary. Micrometastases need the presence of growth factor and vascular growth factor so that they can form macrometastasis. In addition, cell adhesion molecules (CAMs) and guanine nucleotide exchange factors (GEFs) play important roles in the progression of colorectal cancer and metastatic migration. Further elucidation of the mechanisms of how these molecules contribute will aid in the identification of diagnostic and prognostic markers as well as therapeutic targets for patients with colorectal metastasis.

• 정보화연구
• /
• 제10권1호
• /
• pp.1-11
• /
• 2013

Various computing systems are used in naval ships. Since each system has a single purpose and its applications are tightly coupled with the physical machine, applications cannot share physical resources with each other. It is hard to utilize resources efficiently in conventional naval shipboard computing environment. In this paper, we present an integration architecture for virtualized naval shipboard computing systems based on open architecture. Our proposed architecture integrates individual computing resources into one single integrated hardware pool so that the OS and applications are encapsulated as a VM. We consider the issue of varying needs of all applications in a naval ship that have different purposes, priorities and requirements. We also present parallel VM migration algorithm that improves the process time of resource reallocation of given architecture. The evaluation results with the prototype system show that our algorithm performs better than conventional resource reallocation algorithm in process time.