• Title/Summary/Keyword: Migration patterns

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The Electrochemical Migration Phenomenon of the Ni-Cr Seed Layer of Sputtered FCCL

  • Ahn, Woo-Young;Jang, Joong Soon
    • Journal of the Korean institute of surface engineering
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    • v.47 no.2
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    • pp.63-67
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    • 2014
  • As the demand for fine-pitch FPCB (Flexible Printed Circuit Board) increases, so do the number of applications of sputtered FCCL (Flexible Copper Clad Laminate). Furthermore, as the width between the circuit patterns decreases, greater defects are observed in the migration phenomenon. In this study we observed changes in ion migration in real circuit-pattern width using sputtered FCCL. We found that as the applied voltage and residue thickness of the NiCr seeds increase, ion migration occurs faster. If the NiCr seed layer thickens due to a high cathode power and long deposition time while being sputtered, the NiCr will form a residue that quickly becomes a factor for incurring ion migration.

Patterns of Vertical Distribution and Diel Vertical Migration of Zooplankton in the East Sea of Korea (Sea of Japan)

  • Park, Chul;Lee, Chang-Rae;Hong, Sung-Yun
    • Journal of the korean society of oceanography
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    • v.32 no.1
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    • pp.38-45
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    • 1997
  • To find out the changes in vertical distribution patterns over the 24-h period, a key and the first step to tackle the problem of adaptive significance of diel vertical migration (DVM), vertically stratified time series samplings with multiple opening/closing plankton samplers were done in the East Sea of Korea (Sea of Japan). Sampling was done almost every 4 h for one day period following the same water parcel in Nov. 1995 and May 1996, respectively. Resultant patterns of vertical distribution showed that some species such as most abundant taxa Metridia pacifica and Scolecithyicella minor, both Copepoda, performed DVM even in the study area of strong thermal stratification. Their patterns of DVM such as distance scales and timing of movements were not the same each other, and they were separated from other taxa in the dendrogram obtained by the cluster analyses, Most minor taxa grouped in one, however, seemed not to do DVM in the study area of strong thermal stratification. They usually preferred the warmer surface layer where the foods were probably more abundant.

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Biogeography and Distribution Pattern of a Korean Wood-eating Cockroach Species, Cryptocercus kyebangensis, Based on Genetic Network Analysis and DNA Sequence Information

  • Park, Yung-Chul;Choe, Jae-Chun
    • Journal of Ecology and Environment
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    • v.30 no.4
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    • pp.331-340
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    • 2007
  • We examined the evolutionary and ecological processes shaping current geographical distributions of a Korean wood-eating cockroach species, Cryptocercus kyebangensis. Our research aims were to understand evolutionary pattern of DNA sequences, to construct genetic network of Cryptocercus kyebangensis local populations and to understand evolutionary and ecological processes shaping their current geographical distribution patterns via DNA sequence information and genetic networks, using sequence data of two genes (ITS-2 and AT region) from local populations of C. kyebangensis. The results suggest that the ITS-2 and AT region are appropriate molecular markers for elucidating C. kyebangensis geographic patterns at the population level. The MSN-A based on the ITS-2 showed two possible routes, the Hwaak-san and Myeongji-san route and the Seorak-san and Gyebang-san route, for migration of ancestral C. kyebangensis into South Korea. The MSNs (MSN-A and -B) elucidate migration routes well within South Korea, especially the route of Group I and Group II.

Chungbuk Province's Migration Characters Based on the Centrality Indicators : Comparative Observations of 2001 and 2008 Examples (중앙성 지표에 따른 충청북도 인구이동 특성 : 2001년과 2008년 사례 비교분석)

  • Park, Ju-Hye;Hong, Sung-Ho;Ahn, Yoo-Jeong;Lee, Man-Hyung
    • Journal of the Korean association of regional geographers
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    • v.16 no.4
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    • pp.369-386
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    • 2010
  • Migration usually derived from the gap of spatial efficiency and the attractiveness difference between the origin and the destination puts forth significant impact on the regional dynamics of population. Both migration and regional planning or policy are structurally interconnected, exerting impact each other within the circular loops. In order to observe migration characters in the regional dimension, this research depends on social network analysis(SNA) methods which easily portray interrelationship and its weight between the origin and the destination. In specific, it focuses on the application of centrality indicators in order to understand the in- and out-migration patterns and visualize them with spring graphs, pinpointing the in- and out-migration administrative units. This research deals with three migration patterns in 2001 and 2008, respectively: i) in- and out-migration between the nation and Chungbuk Province; ii) in- and out-migration within Chungcheong Areas; and iii) in- and out-migration within Chungbuk Province. Judging from Chungbuk examples, the highest in-migration was recorded at Heungduck District in terms of in- and out-migration between the nation and Chungbuk Province. Seoul and Gyeonggi were two major origins towards Chungbuk Province. Within Chungcheong Areas, Daejeon produced the highest in-migration in 2001. However, Chungnam took that position in 2008.

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Batik characteristics of the Chinese minority Miao (중국 소수민족 묘족(苗族) 납염의 특성)

  • Long, Lulu;Lee, Younhee
    • Journal of the Korea Fashion and Costume Design Association
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    • v.23 no.3
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    • pp.23-42
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    • 2021
  • The purpose of this study is to analyze the characteristics of the Chinese Miao people's Batik patterns and provide data in the field of fashion design for the utilization of the traditional patterns. This study investigated and analyzed the regional characteristics of Batik dyeing, which was listed on China's national intangible cultural heritage list; Danzhai, Anshun, Huangping, and Gonghyeon. The expressive characteristics were classified into four categories: symbolism, abstraction, decorativeness, and playfulness. The results are as follows. First, symbolism can be classified into the origins of the Miao, symbols of faith, history of migration, and the symbols of status with Batik patterns from different regions, seemingly involving various symbolic implications. Due to the absence of letters, Miao people expressed their emotions and history in the design patterns. A series of developments in recent years has led to incorporating the temperament of the Miao people, history of migration, expression of emotions, and ideal hopes in Batik dyed design patterns and the symbolic functions have been significantly emphasized. Second, the decorativeness is mainly characterized by repeated patterns of the Miao Batik dyeing design. The overall patterns demonstrate design features characterized by regularization and simplification, along with a sense of rhythm with the unique arrangement of patterns. Third, the abstractness of the Batik dyeing design patterns is often found in plant and animal patterns, properly delivering new designs created by Miao women by extracting and rearranging various elements, including dots, lines, and faces shown in natural images. Fourth, playfulness is expressed by the transformation and distortion of Miao Batik patterns, and were created by applying patterns or other elements to original forms to express animal or plant patterns in a playful way.

A Resource Reduction Scheme with Low Migration Frequency for Virtual Machines on a Cloud Cluster

  • Kim, Changhyeon;Lee, Wonjoo;Jeon, Changho
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.7 no.6
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    • pp.1398-1417
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    • 2013
  • A method is proposed to reduce excess resources from a virtual machine(VM) while avoiding subsequent migrations for a computer cluster that provides cloud service. The proposed scheme cuts down on the resources of a VM based on the probability that migration may occur after a reduction. First, it finds a VM that can be scaled down by analyzing the history of the resource usage. Then, the migration probability is calculated as a function of the VM resource usage trend and the trend error. Finally, the amount of resources needed to eliminate from an underutilized VM is determined such that the migration probability after the resource reduction is less than or equal to an acceptable migration probability. The acceptable migration probability, to be set by the cloud service provider, is a criterion to assign a weight to the resource reduction either to prevent VM migrations or to enhance VM utilization. The results of simulation show that the proposed scheme lowers migration frequency by 31.6~60.8% depending on the consistency of resource demand while losing VM utilization by 9.1~21.5% compared to other known approaches, such as the static and the prediction-based methods. It is also verified that the proposed scheme extends the elapsed time before the first occurrence of migration after resource reduction 1.1~2.3-fold. In addition, changes in migration frequency and VM utilization are analyzed with varying acceptable migration probabilities and the consistency of resource demand patterns. It is expected that the analysis results can help service providers choose a right value of the acceptable migration probability under various environments having different migration costs and operational costs.

Reviews of Rural In-Migration Studies and Its Practical Implications (도시민 농촌이주에 대한 주요쟁점과 시사점)

  • Lee, Min-Soo;Park, Duk-Byeong
    • Journal of Agricultural Extension & Community Development
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    • v.18 no.1
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    • pp.1-33
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    • 2011
  • In-migration has long been recognized as on important factor in rural development. Its impact can be expected to increase even further as the elderly population continues to grow. Recently with the retirement of baby boomers, postretirement moves have become increasingly important issue in rural Korea. Because the consequences of rural in-migration are often most pronounced at the local or regional level, rural planners are among the many scholars and practitioners seeking to understand the patterns and consequences of in-migration. At the same time, however, planners have sometimes overlooked basic research on the causes and determinants of mobility, and on the relationships between retirement migration and other socioeconomic processes. The papers aims to explore the reviews of rural in-migration studies and its practical implications, providing an interdisciplinary review of the most important studies published between 1990-2009. Through the literature review of in-migration, this study suggests that main arguments for rural in-imgration studies such as rural populations, counterurbanization, rural businesses incubator and rural amenity be emphasized to vitalize and diversify rural economies.

Flux residue effect on the electrochemical migration of Sn-3.0Ag-0.5Cu (Sn-3.0Ag-0.5Cu 솔더링에서 플럭스 잔사가 전기화학적 마이그레이션에 미치는 영향)

  • Bang, Jung-Hwan;Lee, Chang-Woo
    • Journal of Welding and Joining
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    • v.29 no.5
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    • pp.95-98
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    • 2011
  • Recently, there is a growing tendency that fine-pitch electronic devices are increased due to higher density and very large scale integration. Finer pitch printed circuit board(PCB) is to be decrease insulation resistance between circuit patterns and electrical components, which will induce to electrical short in electronic circuit by electrochemical migration when it exposes to long term in high temperature and high humidity. In this research, the effect of soldering flux acting as an electrical carrier between conductors on electrochemical migration was investigated. The PCB pad was coated with OSP finish. Sn3.0Ag0.5Cu solder paste was printed on the PCB circuit and then the coupon was treated by reflow process. Thereby, specimen for ion migration test was fabricated. Electrochemical migration test was conducted under the condition of DC 48 V, $85^{\circ}C$, and 85 % relative humidity. Their life time could be increased about 22% by means of removal of flux. The fundamentals and mechanism of electrochemical migration was discussed depending on the existence of flux residues after reflow process.

Measurement of vertical migration speed of Sound Scattering Layer using an bottom mooring type Acoustic Doppler Current Profiler (해저설치형 음향도플러유향유속계를 이용한 음향산란층의 연직이동속도 측정)

  • Jo, Hyeon-Jeong;Lee, Kyoung-Hoon
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.46 no.4
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    • pp.449-457
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    • 2010
  • This study shows that the vertical migration speed of sound scattering layers (SSLs), which is distributed in near Funka Bay, were measured by 3D velocity components acquired from a bottom moorng ADCP. While the bottom mooring type has a problem to measure the velocity vectors of sound scattering layer distributed near to surface, both the continuous vertical migration patterns and variability of backscatterers were routinely investigated as well. In addition, the velocity vectors were compared with the vertical migration velocity estimated from echograms of Mean Volume Backscattering Strength, and estimated to produce observational bias due to SSLs which is composed of backscatterers such as euphausiids, nekton, and fishes have swimming ability.

Exploratory Spatial Data Analysis (ESDA) for Age-Specific Migration Characteristics : A Case Study on Daegu Metropolitan City (연령별 인구이동 특성에 대한 탐색적 공간 데이터 분석 (ESDA) : 대구시를 사례로)

  • Kim, Kam-Young
    • Journal of the Korean association of regional geographers
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    • v.16 no.5
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    • pp.590-609
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    • 2010
  • The purpose of the study is to propose and evaluate Exploratory Spatial Data Analysis(ESDA) methods for examining age-specific population migration characteristics. First, population migration pyramid which is a pyramid-shaped graph designed with in-migration, out-migration, and net migration by age (or age group), was developed as a tool exploring age-specific migration propensities and structures. Second, various spatial statistics techniques based on local indicators of spatial association(LISA) such as Local Moran''s $I_i$, Getis-Ord ${G_i}^*$, and AMOEBA were suggested as ways to detect spatial dusters of age-specific net migration rate. These ESDA techniques were applied to age-specific population migration of Daegu Metropolitan City. Application results demonstrated that suggested ESDA methods can effectively detect new information and patterns such as contribution of age-specific migration propensities to population changes in a given region, relationship among different age groups, hot and cold spot of age-specific net migration rate, and similarity between age-specific spatial clusters.

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