• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.15 no.2
• /
• pp.149-162
• /
• 2012

Habitat loss and fragmentation are ongoing major anthropogenic impacts on landscapes, which can strongly affect ecosystems, populations and species. The studies on forest fragmentation have been progressed, but the studies on definition of forest fragmentation and their synthetic trend in South Korea still leaves much to be desired. Therefore we set the definition of forest fragmentation and reviewed the related papers. We can give a definition that forest fragmentation is not only a process of spatial landscape transformation, but also a process of ecosystem change by it. The trend of studies on forest fragmentation divided into two fields, landscape and ecosystem changes. Forest fragmentation caused by land change altered the composition and configuration of forest patches. Most studies related on that analyzed the change using landscape index. The effects of forest fragmentation on ecosystem subdivided into three fields : biodiversity, edge effects, and invasive species, but the studies in South Korea is short. The study on relations between forest fragmentation and ecosystem change is necessary to face the Convention on Biological Diversity in South Korea. In addition, the fundamental studies on biodiversity is important to mitigate against forest fragmentation.

• Geomechanics and Engineering
• /
• v.16 no.2
• /
• pp.195-204
• /
• 2018

Based on theories of rock mechanics, rock fragmentation, mechanics of elasto-plasticity, and energy dissipation etc., a method is presented for evaluating the rock fragmentation efficiency by using plastic energy dissipation ratio as an index. Using the presented method, the fragmentation efficiency of rocks with different strengths (corresponding to soft, intermediately hard and hard ones) under indentation is analyzed and compared. The theoretical and numerical simulation analyses are then combined with experimental results to systematically reveal the fragmentation mechanism of rocks under indentation of indenter. The results indicate that the fragmentation efficiency of rocks is higher when the plastic energy dissipation ratio is lower, and hence the drilling efficiency is higher. For the rocks with higher hardness and brittleness, the plastic energy dissipation ratio of the rocks at crush is lower. For rocks with lower hardness and brittleness (such as sandstone), most of the work done by the indenter to the rocks is transferred to the elastic and plastic energy of the rocks. However, most of such work is transferred to the elastic energy when the hardness and the brittleness of the rocks are higher. The plastic deformation is small and little energy is dissipated for brittle crush, and the elastic energy is mainly transferred to the kinetic energy of the rock fragment. The plastic energy ratio is proved to produce more accurate assessment on the fragmentation efficiency of rocks, and the presented method can provide a theoretical basis for the optimization of drill bit and selection of well drilling as well as for the selection of the rock fragmentation ways.

• The KIPS Transactions:PartA
• /
• v.8A no.4
• /
• pp.331-338
• /
• 2001

With the general use of network, cyber terror rages throughout the world. However, IP Fragmentation isn\`t free from its security problem yet, even though it guarantees effective transmission of the IP package in its network environment. Illegal invasion could happen or disturb operation of the system by using attack mechanism such as IP Spoofing, Ping of Death, or ICMP taking advantage of defectiveness, if any, which IP Fragmentation needs improving. Recently, apart from service refusal attack using IP Fragmentation, there arises a problem that it is possible to detour packet filtering equipment or network-based attack detection system using IP Fragmentation. In the paper, we generate the real time access log file to make the system manager help decision support and to make the system manage itself in case that some routers or network-based attack detection systems without packet reassembling function could not detect or suspend illegal invasion with divided datagrams of the packet. Through the implementation of the self-managing system we verify its validity and show its future effect.

• Journal of Korea Society of Digital Industry and Information Management
• /
• v.16 no.2
• /
• pp.11-25
• /
• 2020

This study proposes a method to manipulate fragmentation of disks by arbitrarily allocating and releasing the status of a disk cluster in the NTFS file system. This method allows experiments to be performed in several studies related to fragmentation problems on disk cluster. Typical applicable research examples include testing the performance of disk defragmentation tools according to the state of fragmentation, establishing an experimental environment for fragmented file carving methods for digital forensics, setting up cluster fragmentation for testing the robustness of data hiding methods within directory indexes, and testing the file system's disk allocation methods according to the various version of Windows. This method suggests how a single file occupies a cluster and presents an algorithm with a flowchart. It raises three tricky problems to solve the method, and we propose solutions to the problems. Experiments for allocating the disk cluster to be fragmented to the maximum extent possible, it then performs a disk defragmentation experiment to prove the proposed method is effective.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.2 no.3
• /
• pp.16-22
• /
• 1999

The various spatial structure of biological habitat has tighten relationship with biodiversity. Due to increasing of population, development of agriculture and urban structure, various change of landscape has became these days. These change of landscape has raised the decrease of habitat and landscape fragmentation. This paper summarizes research to analysis vegetation index according to P/A ratio, Shape Index, and Fractal dimension using Landsat Thematic Mapper(TM). The analysis of landscape fragmentation using NDVI(Normalized Difference Vegetation Index) 0.5~1 has the most profitable for detection of vegetation fragmentation. The analysis of vegetation index of Seoul and Kyunggi province has also showed that Fractal dimension has the most fragmentation index. In near future, time series analysis is needed for fragmentation of vegetation on the same area, and for various landuse of fragmentation analysis. These researches were carried out for preservation strategy of vegetation and biodiversity.

• Clinical and Experimental Reproductive Medicine
• /
• v.46 no.4
• /
• pp.147-151
• /
• 2019

Objective: The aim of this study was to investigate DNA fragmentation status in human spermatozoa according to specific tail swelling patterns determined via hypo-osmotic swelling test (HOST). Methods: Frozen semen samples from 21 healthy donors were thawed and prepared by the swim-up technique for use in intracytoplasmic sperm injection. The semen samples were treated for 5 minutes as part of the HOST procedure and then underwent the sperm chromatin dispersion test using a Halosperm kit. DNA fragmentation status (large halo, medium halo, small halo, no halo, or degraded) and the specific tail swelling pattern ("a"-"g") were assessed at the level of a single spermatozoon. A total of 42,000 spermatozoa were analyzed, and the percentage of spermatozoa without DNA fragmentation (as evidenced by a large or medium halo) was assessed according to the specific tail swelling patterns observed. Results: The HOST examinations showed that > 93% of spermatozoa across all types displayed no DNA fragmentation. The percentage of spermatozoa without DNA fragmentation was 100% in type "d", 98.67% in type "g", and 98.17% in type "f" spermatozoa. Conclusion: We found that the type "d" spermatozoa displayed no DNA fragmentation, but the other types of spermatozoa also displayed very low rates of DNA fragmentation. This result may be associated with the processing of the spermatozoa by density gradient centrifugation and the swim-up technique.

• Korean Journal of Microbiology
• /
• v.35 no.1
• /
• pp.28-34
• /
• 1999

Fragmentation vectors are used to analyze function and genomic structure of a gene of interest by creating deletion derivatives of large fragments of genomic DNA cloned as yeast artificial chromosomes (YACs). Herein, we developed a new hicistronic fragmentation vector that contains internal ribosomal entry sile (IRES) of encephalomyocarditis vin~s (EMCV) and $\beta$-galactosidase as a reporter gene. This vector system provides a novcl loo1 to analyze expression patterns of a gene of interest due to simultaneous expression of a target gene as well as $\beta$-galactosidase driven from a single message. In addition, the bicistronic fragmentation vector contains four rare-cutting restriction enzyme sites in the polycloning sites which can be used to conveniently insert any kinds of genes and therefore facilitates targeting DNA scgments into YAC by means of homologous recombination. This approach establishes a paradigm for manipulation of mammalian DNA segments and characterization of expression and regulatory regions of mammalian gene cloned as YAC.

• Bulletin of the Korean Chemical Society
• /
• v.35 no.9
• /
• pp.2774-2780
• /
• 2014

A dynamics study of relaxation and fragmentation of icosahedral argon cluster with a vibrationally excited $Ar_2^+$ (${\nu}$) is presented. Local translation is shown to be responsible for inducing energy flow from the embedded ion to host atoms and fragmentation of the cluster consisting of various low frequency modes. The total potential energy of $(Ar_2^+)Ar_{12}$ is formulated using a building-up procedure of host-guest and host-host interactions. The time dependence of ion-to-host energy transfer is found to be tri-exponential, with the short-time process of ~100 ps contributing most to the overall relaxation process. Relaxation timescales are weakly dependent on both temperature (50-300 K) and initial vibrational excitation (${\nu}$ = 1-4). Nearly 27% of host atoms in the cluster with $Ar_2^+$ (${\nu}$ = 1) fragment immediately after energy flow, the extent increasing to ~43% for ${\nu}$ = 4. The distribution of fragmentation products of $(Ar_2^+)Ar_{12}{\rightarrow}(Ar_2^+)Ar_n+(12-n)Ar$ are peaked around $(Ar_2^+)Ar_8$. The distribution of dissociation times reveals fragmentation from one hemisphere dominates that from the other. This effect is attributed to the initial fragmentation causing a sequential perturbation of adjacent atoms on the same icosahedral five-atom layer.

• Journal of Ocean Engineering and Technology
• /
• v.12 no.3 s.29
• /
• pp.31-41
• /
• 1998

Single fiber fragmentation technique was used to evaluate the change of interfacial properties by degradation of fiber tensile strength in the fiber reinforced composites. The influences of fiber tensile strength on the interfacial properties have been evaluated by the fragmentation specimens(weak fiber samples) of glass fiber/epoxy resin that was made using the pre-degraded glass fiber in distilled water at $80^{circ}C$ for specified periods. The effects of the immersion time on the interfacial properties in the distilled water at $80^{circ}C$ also have been evaluated by the fragmentation specimens(original fiber samples) of glass fiber/epoxy resin that was made using the received glass fiber. As the result, the tensile strength of glass fiber was decreased with the increasing of the treatment time in the distilled water at $80^{circ}C$ and the interfacial shear strength was independent of the change of the glass fiber strength in the single fiber fragmentation test. But in the durability test using the single fiber fragmentation specimen, interfacial shear strength decreased with the increasing of the immersion time in distilled water ar $80^{circ}C$. And it turned out that the evaluating of interfacial shear strength using original fiber tensile strength was valuable in the durability test for the water environment by the single fiber fragmentation technique.

• Journal of the Korean Society of Costume
• /
• v.57 no.6 s.115
• /
• pp.145-159
• /
• 2007

Freed from its traditional confinement to the human body, postmodernism in fashion exposes the defectiveness of body and abstracts from the body under. As the 20th century art put premium on self-expression, the body itself became a powerful medium of expression in fashion. Using 'body' to analyze the clothing form, my study develops a framework by which to classify the fragmentation of the body in fashion. In order to inquire the formative style and aesthetic values expressed in fragmentation of the body in fashion, my study examines subjects from the discourse on the body to the fashion collections of the late 20th and 21st century, The results of the study are as follows. Fragmentation of the body in fashion means the break away from the idealized and standardized body for mass productions. It tends to experiment with extreme exaggeration in form, refusing to subscribe to the traditional values that build on the balance and symmetry of the body. The formative aspects of fragmentation are achieved through body casting, displacement, and deconstruction. The absence of physicality in fashion opposes the sartorial convention and symbolism that results in the discord between signifiant and $signifi{\tilde{e}}$ of clothing. Fashion continues to explore forms and images that transcend the traditional representations of the clothed body. As a type of intimate architecture, fashion always mediates the dialogue between clothes and body, or fashion and figure. My study suggests a framework to analyze fragmentation of the body in fashion, focusing on the relationship between the clothes and body.