• Journal of Digital Convergence
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• v.13 no.12
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• pp.319-324
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• 2015

This paper proposes an integrated management system for products of game software development. Those products generated over software life-cycle are generally huge in numbers, various in kinds and interconnected in relationships among them. Especially they are highly complex and tightly coupled each other because they are used to build another world which is composed of multi-modal data such as graphics, sound, logics and so on. Therefore it is critical to manage development products in an integrated manner to guarantee the quality of software. The proposed system is designed to provide project/requirement/configuration/traceability management capabilities and interfacing to CASE standards. To achieve the objective, it is based on data warehouse technologies which provide central repositories of heterogeneous data, multi-aspect reporting&analysis capabilities, traceability, verification, etc.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.603-606
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• 2006

We present a study on the development of a practical and quantitative technique for the assessment of the structural health condition with using piezoceramic(PZT) sensors. The electro-impedance-based technique with the PZT patches is very sensitive for evaluation of the incipient and small damage in a high frequency range, and however the commonly traditional modal analysis method is effective only for considerably larger damages in low frequency range. The paper presents the technique in detecting and characterizing real-time damage on the specimen that is an aluminum plate fastened with bolts and nuts by different torques and as well a plate with a crack. By using the special arrangement of the PZT sensors, the required longitudinal wave is generated through the specimen. A large number of experiments are conducted and the different conditions of the specimens, i.e. the location and extent of loosening bolts, and the plate with a crack are simulated. respectively. Since fixing and loosening the loosened bolt is controlled by a torque wrench, we can control exactly the experiment of the different torques. Compared with the simulated healthy condition, we can find whether or not there is a damage in the specimen with using an impedance analyzer with the PZT sensors. Several indices are discussed and used for assessing the different simulated damages. As for the location of bolt loosening, the RMSD is found to be the most appropriate index for numerical assessment and as well the RMSD shows strongly linear relationship for assessing the extent of the bolt loosening, and the frequency peak shift ${\Delta}F$ is used to assess the cracked plate. The possibility of repeatability of the pristine condition signatures is also presented and the appropriate frequency range and interval are uniquely selected through large numbers of experiments.

• Korean Journal of Ichthyology
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• v.18 no.1
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• pp.20-26
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• 2006

Bagrid catfish hybrid between Korean bullhead (Pseudobagrus fulvidraco) and Ussurian bullhead (Leiocassis ussuriensis) was produced by artificial fertilization. Modal chromosome numbers of Korean bullhead, Ussurian bullhead and their hybrid were the same as 2n=52. The karyotypes were 22 metacentric (M), 22 submetacentacentric (SM), and 8 acrocentric (A) chromosomes for Korean bullhead, 22M+14SM+16A for Ussurian bullhead and 22M+18SM+12A for their hybrid. The hybrid bullhead karyotype consisted of each haploid set of parental species chromosomes. Erythrocytic sizes and DNA contents of hybrids were intermediate between two parental species.

• Journal of Aquaculture
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• v.22 no.1
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• pp.74-78
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• 2009

Backcross hybridization between Korean bullhead Pseudobagrus fulvidraco female and Korean bullhead P. fulvidraco $\times$ Ussurian bullhead Leiocassis ussuriensis hybrid male was performed, and early viability and karyotype of the backcross hybrids were examined along with their parental species. Mean fertilization rate (86.8%), hatching success (70.7%) and early survival rate (76.4%) of backcross hybrids were similar with those found in the maternal species, the Korean bullhead. From the chromosome analysis, modal chromosome numbers of Korean bullhead, Ussurian bullhead, their hybrid and backcross hybrid were the same as 2n = 52. However, their karyotypes were different among genotypes. The karyotype of backcross hybrid was 22 metacentric + 18 submetacentacentric + 12 acrocentric chromosomes.

• Korean Journal of Poultry Science
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• v.13 no.2
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• pp.167-172
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• 1986

Chromosome size, number and shape were studied by the centromeric index, the arm ratio and the relative length of chromosome. The chromosomes of 50 early chick embryos which were derived from a pure line of Single Comb White Leghorns were examined. Using a colchicine, hypotonic treatment, fixation and air-drying technique, the clear prometaphase figures were obtained from the whole embryo. The results of the present investigation of chromosome pairs were as follows, 1. Pair 1 and 2; metacentric and submetacentric chromosomes which could be clearly distinguished from each other by size. 2. Pair 3 and 4: acrocentric chromosomes of similar length but the 4th pair had a distinct short arm which was not present in the 3rd. 3, Pair 5; metacentric sex chromosomes, 2 chromosome had relative 5th length but the W chromosome had slightly shorter length than 7th pair of chromosomes. 4. Pair 6; acrocentric chromosomes similar in shape to pair 3 but of little more than half the size. 5, Pair 7 and 8; acrocentric chrocentric but the 7th pairs had a definite short arm. 6. Pair 9; similar length to the 7, 8 pairs but had a medially placed centromere. 7. microchromosomes of 30 pairs ; nearly all acrocentric chromosomes which appeared as paired dots. The total number of diploid was appeared to 72-78. But a number of observations presented the total diploid number in 78 (58%). The inconstancy in number observed in this study was presumably due to the minute size of the microchromosomes. Thus, the modal numbers for the diploid chromosome was at least 78.

• Journal of the Society of Naval Architects of Korea
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• v.30 no.1
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• pp.65-72
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• 1993

A numerical method for nonlinear free-surface-wave problem is developed in this paper. The final goal of this study is to simulate the towing tank experiment of a ship model and to partially replace the experiment by the numerical model. The exact problem in the scope of potential flow theory is formulated by a variational principle based on the classical Hamilton's principle. A localized finite element method is used in the present numerical computations which made use of the following two notable steps. The first step is an efficient treatment of the numerical radiation condition by using the intermediate nonlinear-to-linear transition buffer subdomain between the fully nonlinear and linear subdomains. The second is the use of a modal analysis in the final stage of the solution procedures, which enables us to reduce the computation time drastically. With these improvements the present method can treat a much larger computational domain than that was possible previously. A pressure patch on the free surface was chosen as an example. From the present computed results we could investigate the effect of nonlinearity on the down-stream wave pattern more clearly than others, because much larger computational domain was treated. We found, specifically, the widening of the Kelvin angle and the increase of the wave numbers and the magnitude of wave profiles.

• Journal of the Society of Naval Architects of Korea
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• v.60 no.5
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• pp.375-387
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• 2023

The subsea power cables are increasingly important for harvesting renewable energies as we develop offshore wind farms located at a long distance from shore. Particularly, the continuous flexural motion of inter-array dynamic power cable of floating offshore wind turbine causes tremendous fatigue damages on the cable. As the subsea power cable consists of the helical structures with various components unlike a mooring line and a steel pipe riser, the fatigue analysis of the cables should be performed using special procedures that consider stick/slip phenomenon. This phenomenon occurs between inner helically wound components when they are tensioned or compressed by environmental loads and the floater motions. In particular, Vortex-induced vibration (VIV) can be generated by currents and have significant impacts on the fatigue life of the cable. In this study, the procedure for VIV fatigue analysis of the dynamic power cable has been established. Additionally, the respective roles of programs employed and required inputs and outputs are explained in detail. Demonstrations of case studies are provided under severely sheared currents to investigate the influences on amplitude variations of dynamic power cables caused by the excitation of high mode numbers. Finally, sensitivity studies have been performed to compare dynamic cable design parameters, specifically, structural damping ratio, higher order harmonics, and lift coefficients tables. In the future, one of the fundamental assumptions to assess the VIV response will be examined in detail, namely a narrow-banded Gaussian process derived from the VIV amplitudes. Although this approach is consistent with current industry standards, the level of consistency and the potential errors between the Gaussian process and the fatigue damage generated from deterministic time-domain results are to be confirmed to verify VIV fatigue analysis procedure for slender marine structures.