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Search Results: 1 - 10 of 55367 matches for " Yong-Jin Park "
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A Radio-Aware Routing Algorithm for Reliable Directed Diffusion in Lossy Wireless Sensor Networks
Yong-Pyo Kim,Euihyun Jung,Yong-Jin Park
Sensors , 2009, DOI: 10.3390/s91008047
Abstract: In Wireless Sensor Networks (WSNs), transmission errors occur frequently due to node failure, battery discharge, contention or interference by objects. Although Directed Diffusion has been considered as a prominent data-centric routing algorithm, it has some weaknesses due to unexpected network errors. In order to address these problems, we proposed a radio-aware routing algorithm to improve the reliability of Directed Diffusion in lossy WSNs. The proposed algorithm is aware of the network status based on the radio information from MAC and PHY layers using a cross-layer design. The cross-layer design can be used to get detailed information about current status of wireless network such as a link quality or transmission errors of communication links. The radio information indicating variant network conditions and link quality was used to determine an alternative route that provides reliable data transmission under lossy WSNs. According to the simulation result, the radio-aware reliable routing algorithm showed better performance in both grid and random topologies with various error rates. The proposed solution suggested the possibility of providing a reliable transmission method for QoS requests in lossy WSNs based on the radio-awareness. The energy and mobility issues will be addressed in the future work.
TinyONet: A Cache-Based Sensor Network Bridge Enabling Sensing Data Reusability and Customized Wireless Sensor Network Services
Eui-Hyun Jung,Yong-Jin Park
Sensors , 2008, DOI: 10.3390/s8127930
Abstract: In recent years, a few protocol bridge research projects have been announced to enable a seamless integration of Wireless Sensor Networks (WSNs) with the TCP/IP network. These studies have ensured the transparent end-to-end communication between two network sides in the node-centric manner. Researchers expect this integration will trigger the development of various application domains. However, prior research projects have not fully explored some essential features for WSNs, especially the reusability of sensing data and the data-centric communication. To resolve these issues, we suggested a new protocol bridge system named TinyONet. In TinyONet, virtual sensors play roles as virtual counterparts of physical sensors and they dynamically group to make a functional entity, Slice. Instead of direct interaction with individual physical sensors, each sensor application uses its own WSN service provided by Slices. If a new kind of service is required in TinyONet, the corresponding function can be dynamically added at runtime. Beside the data-centric communication, it also supports the node-centric communication and the synchronous access. In order to show the effectiveness of the system, we implemented TinyONet on an embedded Linux machine and evaluated it with several experimental scenarios.
Simple Sequence Repeat Polymorphisms (SSRPs) for Evaluation of Molecular Diversity and Germplasm Classification of Minor Crops
Yong-Jin Park,Ju Kyong Lee,Nam-Soo Kim
Molecules , 2009, DOI: 10.3390/molecules14114546
Abstract: Evaluation of the genetic diversity among populations is an essential prerequisite for the preservation of endangered species. Thousands of new accessions are introduced into germplasm institutes each year, thereby necessitating assessment of their molecular diversity before elimination of the redundant genotypes. Of the protocols that facilitate the assessment of molecular diversity, SSRPs (simple sequence repeat polymorphisms) or microsatellite variation is the preferred system since it detects a large number of DNA polymorphisms with relatively simple technical complexity. The paucity of information on DNA sequences has limited their widespread utilization in the assessment of genetic diversity of minor or neglected crop species. However, recent advancements in DNA sequencing and PCR technologies in conjunction with sophisticated computer software have facilitated the development of SSRP markers in minor crops. This review examines the development and molecular nature of SSR markers, and their utilization in many aspects of plant genetics and ecology.
Development of cDNA-derived SSR markers and their efficiency in diversity assessment of Cymbidium accessions
Moe,Kyaw Thu; Hong,Woo-Ju; Kwon,Soon-Wook; Park,Yong-Jin;
Electronic Journal of Biotechnology , 2012,
Abstract: cymbidium spp. are popular ?owering plants. assessment of the genetic diversity in cultivated cymbidium facilitates conservation of germplasm and subsequent cultivar improvement. thus, it is important to develop more efficient polymorphic dna markers. although more motifs (403) were identified and more primers (206) were designed in the genomic library compared to the cdna library, a larger number of successful primers were obtained from the cdna library (59.9%) than from genomic dna library (51.1%). however, higher pic and gene diversity were identified in genomic ssrs. the average allele number per locus was also higher in genomic ssrs (7.3) than est-ssrs (5.2), among the 24 evaluated cymbidium accessions. at/ta was comparatively high in est-ssrs, while this motif was not as common in genomic ssrs. the ctt/aag/tct/aga/ttc/gaa and tgc/gca/gct/agc/ctg/cag motifs were the most abundant tri-nucleotide sequences in est-ssrs, while gtt/aac/tgt/aca/ttg/caa was the most frequent in genomic ssrs. the number of repeats ranged from 3 to 12 in est-ssrs. currently, 52 novel polymorphic ssr markers have been evaluated, which will be useful for germplasm assessments, core set construction, evaluation of genetic diversity, and marker assisted selection (mas) based cymbidium breeding.
Comparison of Population Genetic Structures between Asian and American Mungbean Accessions Using SSR Markers
Xiao-Qiang Wang,Soon-Wook Kwon,Yong-Jin Park
Journal of Agricultural Science , 2012, DOI: 10.5539/jas.v4n9p150
Abstract: The purpose of this study was to evaluate the genetic diversity and population structure of 65 mungbean accessions collected from East and Southeast Asia, the United States and Guatemala using 15 simple sequence repeat (SSR) markers. In total, 47 alleles were detected, the number of the alleles per locus range from two to six, with an average of 3.13. The mean major allele frequency (MAF), expected heterozygosity (HE), and polymorphic information content (PIC) of the 15 SSR loci were 0.76, 0.05, and 0.28, respectively. Of the 47 alleles, 17 (36.2%) were common, with a frequency of 0.05– 0.5; 16 (34.0%) were rare (frequency < 0.05) and 14 (29.8%) were abundant (frequency > 0.5). On the basis of the UPGMA dendrogram, most of the accessions were clustered into two main groups. The first group (Group I) included seven accessions and the second comprised 58 accessions, which were further divided into four subgroups. Four subpopulations were detected by model-based structure analysis. Fifty-five accessions (84.6%) showed a clear relation to each cluster based on their inferred ancestry value (>75%), while the remaining 10 accessions (15.4%) were categorized as admixtures. Mungbean accessions from US distributed to almost all clusters and 2 accessions shared genetic constituents showing it derived from mixed ancestry with Asean accessions. These results could be useful in identifying mungbean germplasms and facilitating their improvement programs.
Orbital Interaction and Electron Density Transfer in PdII([9]aneB2A)L2 Complexes: Theoretical Approaches
Ock Keum Kwak,Mahreen Arooj,Yong-Jin Yoon,Euh Duck Jeong,Jong Keun Park
Molecules , 2013, DOI: 10.3390/molecules181012687
Abstract: The geometric structures of Pd-complexes {Pd([9]ane B 2 A) L 2 and Pd([9]ane BAB) L 2 where A = P, S; B = N; L = PH 3, P(CH 3) 3, Cl ?}, their selective orbital interaction towards equatorial or axial (soft A…Pd) coordination of macrocyclic [9]ane B 2 A tridentate to Pd L 2, and electron density transfer from the electron-rich trans L-ligand to the low-lying unfilled a 1g(5s)-orbital of Pd L 2 were investigated using B3P86/lanl2DZ for Pd and 6-311+G** for other atoms. The pentacoordinate endo-[Pd([9]ane B 2 A)( L-donor) 2] 2+ complex with an axial (soft A--Pd) quasi-bond was optimized for stability. The fifth (soft A--Pd) quasi-bond between the σ-donor of soft A and the partially unfilled a 1g(5s)-orbital of Pd L 2 was formed. The pentacoordinate endo-Pd([9]ane B 2 A)( L-donor) 2] 2+ complex has been found to be more stable than the corresponding tetracoordinate endo-Pd complexes. Except for the endo-Pd pentacoordinates, the tetracoordinate Pd([9]ane BAB) L 2 complex with one equatorial (soft A-Pd) bond is found to be more stable than the Pd([9]ane B 2 A) L 2 isomer without the equatorial ( A-Pd) bond. In particular, the geometric configuration of endo-[Pd([9]ane PNP)( L-donor) 2] 2+ could not be optimized.
Surface Morphology and Sensing Property of NiO-WO3 Thin Films Prepared by Thermal Evaporation
Dong-myong Na,L. Satyanarayana,Gwang-Pyo Choi,Yong-Jin Shin,Jin Seong Park
Sensors , 2005, DOI: 10.3390/s5120519
Abstract: WO3 and NiO-WO3 thin films of various thicknesses were deposited on anAl2O3-Si (alumina-silicon) substrate using high vacuum thermal evaporation. Afterannealing at 500oC for 30 minutes in air, the crystallanity and surface morphology of WO3and NiO-WO3 thin films were investigated using X-ray diffraction (XRD) and ScanningElectron Microscopy (SEM). It is observed that the WO3 thin films were resulted in cracksbetween the polycrystalline grains and the grain growth was increased with increasingthickness causing deteriorated sensing characteristics of the films. On the other hand, anoptimum deposition of NiO on WO3 thin film has inhibited the grain growth and improvedthe sensitivity of the films. The inhibition is limited to a certain thickness of WO3 and NiOcontent (mol %) of inclusion and below or above this limitation the grain growth could notbe suppressed. Moreover, the deposition sequence of NiO and WO3 is also playing asignificant role in controlling the grain growth. A probable mechanism for the control ofgrain growth and improving the sensing property has been discussed.
Geographic Variation in Advertisement Calls in a Tree Frog Species: Gene Flow and Selection Hypotheses
Yikweon Jang, Eun Hye Hahm, Hyun-Jung Lee, Soyeon Park, Yong-Jin Won, Jae C. Choe
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0023297
Abstract: Background In a species with a large distribution relative to its dispersal capacity, geographic variation in traits may be explained by gene flow, selection, or the combined effects of both. Studies of genetic diversity using neutral molecular markers show that patterns of isolation by distance (IBD) or barrier effect may be evident for geographic variation at the molecular level in amphibian species. However, selective factors such as habitat, predator, or interspecific interactions may be critical for geographic variation in sexual traits. We studied geographic variation in advertisement calls in the tree frog Hyla japonica to understand patterns of variation in these traits across Korea and provide clues about the underlying forces for variation. Methodology We recorded calls of H. japonica in three breeding seasons from 17 localities including localities in remote Jeju Island. Call characters analyzed were note repetition rate (NRR), note duration (ND), and dominant frequency (DF), along with snout-to-vent length. Results The findings of a barrier effect on DF and a longitudinal variation in NRR seemed to suggest that an open sea between the mainland and Jeju Island and mountain ranges dominated by the north-south Taebaek Mountains were related to geographic variation in call characters. Furthermore, there was a pattern of IBD in mitochondrial DNA sequences. However, no comparable pattern of IBD was found between geographic distance and call characters. We also failed to detect any effects of habitat or interspecific interaction on call characters. Conclusions Geographic variations in call characters as well as mitochondrial DNA sequences were largely stratified by geographic factors such as distance and barriers in Korean populations of H. japoinca. Although we did not detect effects of habitat or interspecific interaction, some other selective factors such as sexual selection might still be operating on call characters in conjunction with restricted gene flow.
Growth Dynamics and Gas Transport Mechanism of Nanobubbles in Graphene Liquid Cells
Dongha Shin,Jong Bo Park,Yong-Jin Kim,Sang Jin Kim,Jin Hyoun Kang,Bora Lee,Sung-Pyo Cho,Byung Hee Hong,Konstantin S. Novoselov
Physics , 2014, DOI: 10.1038/ncomms7068
Abstract: Formation, evolution, and vanishing of bubbles are common phenomena in our nature, which can be easily observed in boiling or falling waters, carbonated drinks, gas-forming electrochemical reactions, etc. However, the morphology and the growth dynamics of the bubbles at nanoscale have not been fully investigated owing to the lack of proper imaging tools that can visualize nanoscale objects in liquid phase. Here we demonstrate, for the first time, that the nanobubbles in water encapsulated by graphene membrane can be visualized by in situ ultrahigh vacuum transmission electron microscopy (UHV-TEM), showing the critical radius of nanobubbles determining its unusual long-term stability as well as two distinct growth mechanisms of merging nanobubbles (Ostwald ripening and coalescing) depending on their relative sizes. Interestingly, the gas transport through ultrathin water membranes at nanobubble interface is free from dissolution, which is clearly different from conventional gas transport that includes condensation, transmission and evaporation. Our finding is expected to provide a deeper insight to understand unusual chemical, biological and environmental phenomena where nanoscale gas-state is involved.
Mitral and Tufted Cells Are Potential Cellular Targets of Nitration in the Olfactory Bulb of Aged Mice
Myung Jae Yang, Sooyeon Sim, Ji Hyun Jeon, Eojin Jeong, Hyoung-Chin Kim, Yong-Jin Park, In-Beom Kim
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0059673
Abstract: Olfactory sensory function declines with age; though, the underlying molecular changes that occur in the olfactory bulb (OB) are relatively unknown. An important cellular signaling molecule involved in the processing, modulation, and formation of olfactory memories is nitric oxide (NO). However, excess NO can result in the production of peroxynitrite to cause oxidative and nitrosative stress. In this study, we assessed whether changes in the expression of 3-nitrotyrosine (3-NT), a neurochemical marker of peroxynitrite and thus oxidative damage, exists in the OB of young, adult, middle-aged, and aged mice. Our results demonstrate that OB 3-NT levels increase with age in normal C57BL/6 mice. Moreover, in aged mice, 3-NT immunoreactivity was found in some blood vessels and microglia throughout the OB. Notably, large and strongly immunoreactive puncta were found in mitral and tufted cells, and these were identified as lipofuscin granules. Additionally, we found many small-labeled puncta within the glomeruli of the glomerular layer and in the external plexiform layer, and these were localized to mitochondria and discrete segments of mitral and tufted dendritic plasma membranes. These results suggest that mitral and tufted cells are potential cellular targets of nitration, along with microglia and blood vessels, in the OB during aging.
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