• 디지털산업정보학회논문지
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• 제10권3호
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• pp.35-40
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• 2014

Many researches have been conducted to achieve improvement in distributed system that connects multiple computer systems via communication lines. Among others, the load balancing and file migration are considered to have significant impact on the performance of distributed system. The dynamic file migration algorithm common in distributed processing system involved complex calculations of decision function necessary for file migration and required migration of control messages for the performance of decision function. However, the performance of this decision function puts significant computational strain on computer. As one single network is shared by all computers, more computers connected to network means migration of more control messages from file migration, causing the network to trigger bottleneck in distributed processing system. Therefore, it has become imperative to carry out the research that aims to reduce the number of control messages that will be migrated. In this study, the learning automata was used for file migration which would requires only the file reference-related information to determine whether file migration has been made or determine the time and site of file migration, depending on the file conditions, thus reflecting the status of current system well and eliminating the message transfer and additional calculation overhead for file migration. Moreover, mathematical model for file migration was described in order to verify the proposed model. The results from mathematical model and simulation model suggest that the proposed model is well-suited to the distributed system.

• KNOM Review
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• 제24권1호
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• pp.1-12
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• 2021

VM (Virtual Machine) live migration은 VM에서 동작하는 서비스의 downtime을 최소화하면서 해당 VM을 다른 서버 노드로 이전시키는 서버 가상화 기술이다. 클라우드 데이터센터에서는 로드밸런싱, 특정 위치 서버로의 consolidation 통한 전력 소비 감소, 서버 유지보수(maintenance) 작업 중에도 사용자에게 무중단 서비스를 제공하기 위한 목적 등으로 VM live migration 기술이 활발히 사용되고 있다. 또한 고장 및 장애 상황이 예측되거나 그 징후가 탐지되는 경우, 예방 및 완화 수단으로 활용될 수 있다. 본 논문에서 우리는 두 가지 선제적(proactive) VNF live migration 방법을 제안하며, 첫 번째 방법은 서버 로드밸런싱에 VNF live migration 기법을 사용하며 두 번째 방법은 고장 예측에 기반하여 고장 회피 목적으로 VNF live migration을 사용한다. 선제적 migration을 위한 예측에 머신러닝(기계학습)을 활용하며 실험을 통해 그 실효성을 검증한다. 특히 두 번째 방법에 대해 vEPC (Virtual Evolved Packet Core)의 고장 상황을 case study한 결과를 제시한다.

• 한국콘텐츠학회논문지
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• 제16권4호
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• pp.555-568
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• 2016

본 연구는 현대 말레이시아를 대상으로 말레이시아의 이민정책(migration policy)과 한국인들의 말레이시아로의 은퇴이주(retire migration)의 조우(遭遇, encounter)의 문화적 특징과 의미, 즉 말레이시아 이민정책의 특징과 한국인들의 말레이시아로의 은퇴이주가 어떻게 상호 조우하고, 또한 그 과정이 어떻게 진행되며, 그 의미는 무엇인지에 관해 이를 말레이시아 이민정책의 사회문화적 맥락 내에서 검토하는데 목적이 있다. 본 연구에서는 문헌조사와 현지조사가 병행되었는데, 특히 현지조사에서는 주요 제보자들(key informants)에 대한 인터뷰(interview)와 관찰(observation) 방법을 주로 활용하였다. 구체적으로 먼저 말레이아 이민정책의 특징을 살펴보고, 이를 한국인들의 말레이시아로의 은퇴이주와 연관시켜 접근함으로써, 말레이시아의 이민정책과 한국인들의 말레이시아로의 은퇴이주와는 어떠한 상호관계가 있으며, 그 문화적 특징과 의미는 무엇인지를 고찰하였다. 본 연구의 결과는 다음과 같다. 말레이시아 은퇴이주는 MM2H(Malaysia My 2nd Home) 제도 및 은퇴이주에 대한 잘못된 이해로 인해 자녀교육을 위한 도구로 변용되어 활용되거나 혹은 은퇴이주 자체를 취미활동이나 여가생활의 일부로 간주하는 경향이 나타났다. 이런 이유로 타국으로의 이주임에도 불구하고 은퇴 및 이주에 대한 체계적인 준비 없이 임하거나 혹은 낭만적인 기대로 임함으로써, 결국 대부분 별다른 성과 없이 귀국하는 사례들이 증가하였다. 본 연구는 말레이시아의 이민정책과 한국인들의 말레이시아로의 은퇴이주를 대상으로 그 특징과 의미를 사회문화적 맥락 내에서 고찰함으로써, 한국과 말레이시아 사이의 인적 교류와 이주를 통한 한국과 말레이시아 사이의 교류와 협력의 문화적 특징과 의미를 이해하고, 나아가 한국과 말레이시아 사이의 교류와 협력을 증진시킬 수 있는 학술적, 실천적 방안을 마련하는 데에도 기여할 수 있을 것으로 기대된다.

• Tribology and Lubricants
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• 제15권4호
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• pp.335-342
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• 1999

Corrosion of the disk has been an ongoing concern for the manufacturers of hard disk drives. With the advent of magnetoresistive (MR) head, very low levels of corrosion and contamination become more critical since the raised defects and corrosion products on the disk surface-anything that heats the MR sensor due to the contact-can distort the output signal of the head. This phenomenon is called as thermal asperity. In this paper, the effect of corrosion as a form of Co migration on the occurrence of thermal asperity in MR drives was investigated. The corrosion test at high temperature (60$^{\circ}C$) and high relative humidity (80%) was emphasized in this study and the testing results at ambient condition were compared. The corrosion on the disks was characterized as the amount of Co ion migration using an ion chromatography (IC) and a time-of-flight secondary ion mass spectroscopy (TOF-SIMS). It is proved that corrosion on the disk surface after storage testing is closely correlated to the amount of Co ions migration from the magnetic layer to disk surfaces and higher Co migration causes more thermal asperities in the drive. In order to reduce Co migration, several methods such as burnishing process and structure of the carbon overcoat were investigated. It is found that the hydrogenated carbon overcoat shows the least Co migration among different types of overcoat layer. However, the most effective way to reduce Co migration is the application of Cr layer between the overcoat and the magnetic alloy layer.

• 한국지역사회생활과학회지
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• 제25권3호
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• pp.321-338
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• 2014

This study was examined the level of satisfaction in rural settlement and analyzed its differences according to various demographic variables and characteristics of urban-rural migration. The analysis was conducted by considering returning farmers residing in rural areas. A statistical analysis was conducted using t-test, one-way ANOVA, and Duncan's multiple-range test with a total of 210 responses. First, satisfaction with the convenience of living facilities varied significantly according to the occupation before urban-rural migration, responses of family members and friends to urban-rural migration, and the initial capital for urban-rural migration. Second, satisfaction with the natural environment varied significantly according to age and reasons for urban-rural migration. Third, satisfaction with the transportation environment varied significantly according to gender, the period of residence after urban-rural migration, and the employment type of the returning farmer. Fourth, satisfaction with neighborliness varied significantly according to parents' occupation, agricultural experience before urban-rural migration, experience in agriculture-related social life before urban-rural migration, reasons for urban-rural migration, the type of urban-rural migration, and the employment type of the returning farmer. Fifth, satisfaction with the agricultural environment varied significantly according to responses of family members and friends to urban-rural migration, the period of residence after urban-rural migration, and reasons for urban-rural migration. Sixth, satisfaction with the housing environment varied significantly according to the residential area, the agricultural experience before urban-rural migration, and the period of residence after urban-rural migration.

• 한국지역사회생활과학회지
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• 제28권4호
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• pp.653-667
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• 2017

The purpose of this study were to investigate the socio-economic impacts of urban-to-rural migration on the rural community and to identify the factors influencing rural residents' recognition of the socio-economic impacts of urban-to-rural migration on the rural community. For the purpose, this study analyzed Korea Rural Economic Institute's rural residents survey(2016), using multiple regression model. The main finding of this study were as follows: Positive social impacts of urban-to-rural migration on rural community were (1) contributing to community sustainability through population growth, (2) contributing to securing agricultural human resources, and others. Negative social impacts of urban-to-rural migration on rural community were (1) increasing unnecessary complaints and deepening distrust, (2) weakening of community consciousness, and others. Positive economic impacts of urban-to-rural migration on rural community were (1) increasing the value of residents' property, (2) contributing to local finance through increased local tax revenue, and others. Negative economic impacts of urban-to-rural migration on rural community were (1) difficulty of scaling farmland due to small-scale farming, (2) land shortage caused by rising land prices, and (3) fierce competition to secure labor force. According to the multiple regression analysis, the major factors influencing rural residents' recognition of the socio-economic impacts of urban-to-rural migration were (1) villagers' general attitude toward urban-to-rural migrants, (2) urban-to-rural migrants' community participation, (3) age, and (4) fitness of village in urban-to-rural migration.

• 동남아시아연구
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• 제20권2호
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• pp.135-178
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• 2010

This study is to seek alternatives for regional governance related to transnational labor migration issues in Southeast Asia. This study examined the present situation and trends of labor migration in the region, reviewed involved transnational issues, and identified the current issues of governance to seek alternatives for regional governance. The increase in cross-border labor migration is no doubt a sign of growth and dynamism of the region and greater integration of their economies. But it also poses complex policy and management issues as well as transnational issues over such as unequal economic profits, illegal migration, human rights, and social security issues. In this reality, regional governance is a very important theme and the efforts to manage their migration inherently involve fundamental conflict and tension between related countries and regions. However, politics and governance of transnational migrant workers in Southeast Asia are still pursued at the national level. To resolve these issues, it is urgently required to secure not only collaboration between the parties concerned but also governance at the regional level. Findings of this study are: First, although labor migration has been a relatively long-time transnational issue, the history of addressing the issue at the regional governance is very short and still inceptive. Second, given its size, labor migration in Southeast Asia requires effective regional governance but no breakthrough was possible due to the conflict of interests between origin and destination countries and the conflict of logic between the labor market and the state. Third, the issue of labor migration is an important element for the formation of economic and socio-cultural communities the ASEAN countries have pursued. Fourth, it is urgently needed to seek alternatives for good and effective regional governance as a key to resolving these issues over migrant workers in Southeast Asia.

• 대한간호학회지
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• 제47권5호
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• pp.676-688
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• 2017

Purpose: The purpose of this study was to analyze the migration patterns of new nurses and experienced nurses and to identify the factors influencing inter-regional migration for solving regional imbalances of clinical nurses in South Korea. Methods: This study involved a secondary analysis of data from the Health Insurance Review and Assessment Service (HIRA). Data were analyzed using descriptive statistics and multiple logistic regression analysis. Results: New nurses tended to migrate from Kyunggi to Seoul. However, experienced nurses tended to migrate from Seoul and Chungchung to Kyunggi. Significant predictors of inter-regional migration among new nurses were location and nurse staffing grade of hospitals. Significant predictors of inter-regional migration among experienced nurses were location, hospital type, nurse staffing grade, ownership of hospitals and age of nurses. Conclusion: Inter-regional migration occupied a small portion of total hospital movement among clinical nurses. The regional imbalances of nurses were not caused by the migration from non-metropolitan areas to Seoul. Nurse shortage problems in the small and medium hospitals of the non-metropolitan area can be solved only through improvement of work environment.

• 한국재료학회지
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• 제15권1호
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• pp.54-60
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• 2005

Recently a lots of problems have observed in high densified and high integrated electronic components. One of them is ion migration phenomena, which induce the electrical short of electrical circuit. ion migration phenomena has been observed in the field of exposing the specific environment and using for a long tin e. This study was evaluated the generation time of ion migration and was investigated properly test method through water drop test and high temperature high humidity test. Also we observed direct causes and confirmed generation mechanism of dendritic growth as we reproduced the ion migration phenomena. We utilized PCB(printed circuit board) having a comb pattern as follows 0.5, 1.0, 2.0 mm pattern distance. Cu, SnPb and Au were electroplated on the comb pattern. 6.5 V and 15 V were applied in the comb pattern and then we measured the electrical short time causing by ion migration. In these results, we examined a difference of ion migration time depending on pattern materials, applied voltage and pattern spacing of PCB conductor.

• BMB Reports
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• 제57권5호
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• pp.250-255
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• 2024

Due to their stem-like characteristics and immunosuppressive properties, Mesenchymal stem cells (MSCs) offer remarkable potential in regenerative medicine. Much effort has been devoted to enhancing the efficacy of MSC therapy by enhancing MSC migration. In this study, we identified deubiquitinase BRCA1-associated protein 1 (BAP1) as an inhibitor of MSC migration. Using deubiquitinase siRNA library screening based on an in vitro wound healing assay, we found that silencing BAP1 significantly augmented MSC migration. Conversely, BAP1 overexpression reduced the migration and invasion capabilities of MSCs. BAP1 depletion in MSCs upregulates ERK phosphorylation, thereby increasing the expression of the migration factor, osteopontin. Further examination revealed that BAP1 interacts with phosphorylated ERK1/2, deubiquitinating their ubiquitins, and thus attenuating the ERK signaling pathway. Overall, our study highlights the critical role of BAP1 in regulating MSC migration through its deubiquitinase activity, and suggests a novel approach to improve the therapeutic potential of MSCs in regenerative medicine.