• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.13 no.3
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• pp.295-301
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• 2008

Bathymetric data collected using a multi-beam echo sounder during marine scientific survey is essential for geologic and oceanographic research works. Accurate measurment of sound velocity profile(SVP) in water-column is important for bathymetric data processing. SVP can vary at different locations during the survey undertaken for wide areas. In addition, an observational error can occur when different equipments(Sound Velocity Profiler, Conductivity Temperature Depth, eXpendable BathyThermograph) are used for measuring SVP at the same water column. In this study, we used an MB-system software to show changes in bathymetry caused by variation of SVP. The analyses showed that the sound velocity(SV) changes due to the depth and thickness of thermocline had more significant effects on the resulting bathymetric data than those of surface mixed layer. The observational errors between SVP measuring instruments did not cause much differneces in the processed bathymetric data. Bathymetric survey line is better to be established to the direction that the change of temperature can be minimize to reduce the variation of SVP during the data acquisition along the survey line.

• The Journal of the Acoustical Society of Korea
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• v.29 no.4
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• pp.223-228
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• 2010

High-frequency bottom loss measurements for grazing angle of $82^{\circ}$ in frequency range 17-40 kHz were made in Jinhae bay in the southern part of Korea. Observations of bottom loss showed the strong variation as a function of frequency, which were compared to the predicted values using two-layered sediment reflection model. The geoacoustic parameters including sound speed, density and attenuation coefficient for the second sediment layer were predicted from the empirical relations with the mean grain size obtained from sediment core analysis. The geoacoustic parameters for the surficial sediment layer were inverted using Monte Carlo inversion algorithm. A sensitivity study for the geoacoustic parameters showed that the thickness of surficial sediment layer was most sensitive to the variation of the bottom loss.

• Journal of the Korean Society for Nondestructive Testing
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• v.24 no.2
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• pp.164-170
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• 2004

Liquid Injection Nozzle(LIN) tube and Calandria tube(CT) in pressurized Heavy Water Reactor (PHWR) are .ross-aligned horizontally. These neighboring tubes can contact each other due to the sag of the calandria tube resulting from the irradiation creep and thermal creep, and fuel load, etc. In order to judge the contact which might be the safety concern, the remote field eddy current (RFEC) technology is applied for the gap measurement in this paper. LIN can be detected by inserting the RFEC probe into pressure tube (PT) at the crossing point directly. To obtain the optimal conditions of the RFEC inspection, the sensitivity, penetration and noise signals are considered simultaneously. The optimal frequency and coil spacing are 1kHz and 200mm respectively. Possible noises during LIN signal acquisition are caused by lift-off, PT thickness variation, and gap variation between PT and CT. The simulated noise signals were investigated by the Volume Integral Method(VIM). Signal analysis on the voltage plane describes the amplitude and shape of LIN and possible defects at several frequencies. All the RFEC measurements in the laboratory were done in variance with the CT/LIN gap and showed the relationship between the LIN gap and the signal parameters by analyzing the voltage plane signals.

• Journal of Animal Science and Technology
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• v.52 no.2
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• pp.157-164
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• 2010

We investigated the influence of carcass traits on carcass price for Hanwoo cow using multiple regression and path analyses. Data for carcass traits and price were collected on mature Hanwoo cow raised in private farms in Kangwon province that were slaughtered in 2008. A total of 96 animals with the average slaughter age of 51 months were used in the current study. Of the carcass traits studied, marbling score (MAR), dressing percentage (DP), and eye-muscle area (EMA) showed moderate and positive correlations with auction price (AP), while correlation coefficients of meat yield index (MINDEX) with AP were low or even negligible. In multiple regression analyses of AP and carcass price (CP) on cold carcass weight (CWT), back fat thickness (BFT), EMA, MAR, and DP, estimates of $R^2$ were 69.86 and 85.43%, respectively. Partial regression coefficients for CWT, BFT, EMA, MAR and DP were -0.028, -0.106, 0.107, 0.814, and 0.075 in the equation of AP and 0.561, -0.060, 0.083, 0.590, and 0.051 in the equation of CP. In path analyses, MAR's total contribution on the variation of AP was largest (0.667), and the total contributions of MAR and CWT on the variation of CP were 0.403 and 0.397. The current study suggested that marbling was the most influential trait on the variation of auction price, and marbling and cold carcass weight were critical traits on the variation of carcass price.

• Journal of Korean Society of Forest Science
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• v.100 no.2
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• pp.226-231
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• 2011

Ulmus davidiana var. japonica is a deciduous tree species used for traditional medicine. This study was conducted to investigate the variation of samara, seed, germination and growth characteristics among populations and among individuals within five natural populations of U. davidiana var. japonica distributed in Korea. The ten characteristics of samara and seed, the three germination behaviors as well as the two growth traits were studied in samaras collected from total 32 trees. Statistical analysis of all characteristics showed that there were significant differences among populations as well as among individuals within populations. In this study, the mean characteristics of this species were 13.0 mm in samara length, 9.7 mm in samara width, 1.37 in samara index, 0.015 g in samara weight, 3.07 mm in samara stalk length, 3.85 seed length, 2.66 mm in seed width, 1.46 in seed index, 1.29 mm seed thickness, 0.0062 g in seed weigh, 34.8% in germination percentage, 8.6 days in mean germination time, 3.5 ea./day in gemination rate, 37.7 cm in height and 4.90 mm in root collar diameter. Especially, coefficients of variations in samara weight, germination percentage, germination rate, height and root collar diameter were relatively high (${\geq}30.0%$) compared to other traits. There was no significant relationship between population association and geographical distribution. The results of principal component analysis for 15 characteristics showed that primary four principal components (PC's) explained 100% of the total variation. The first PC accounted for 41.8% of the variability which correlated with morphological traits, the second PC accounted for 32.9% of the variability which correlated with germination behaviors and the third PC accounted for 16.3% of the variability which correlated with growth traits.

• The Journal of Korean Society for Radiation Therapy
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• v.24 no.1
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• pp.31-37
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• 2012

Purpose: This study evaluated the usefulness of Helmet bolus device using Bolx-II, paraffin wax, solid thermoplastic material in total scalp irradiation. Materials and Methods: Using Rando phantom, we applied Bolx-II (Action Products, USA), paraffin wax (Densply, USA), solid thermoplastic material (Med-Tec, USA) on the whole scalp to make helmet bolus device. Computed tomography (GE, Ultra Light Speed16) images were acquired at 5 mm thickness. Then, we set up the optimum treatment plan and analyzed the variation in density of each bolus (Philips, Pinnacle). To evaluate the dose distribution, Dose-homogeneity index (DHI, $D_{90}/D_{10}$) and Conformity index (CI, $V_{95}/TV$) of Clinical Target Volume (CTV) using Dose-Volume Histogram (DVH) and $V_{20}$, $V_{30}$ of normal brain tissues. we assessed the efficiency of production process by measuring total time taken to produce. Thermoluminescent dosimeters (TLD) were used to verify the accuracy. Results: Density variation value of Bolx-II, paraffin wax, solid thermoplastic material turned out to be $0.952{\pm}0.13g/cm^3$, $0.842{\pm}0.17g/cm^3$, $0.908{\pm}0.24g/cm^3$, respectively. The DHI and CI of each helmet bolus device which used Bolx-II, paraffin wax, solid thermoplastic material were 0.89, 0.85, 0.77 and 0.86, 0.78, 0.74, respectively. The result of Bolx-II was the best. $V_{20}$ and $V_{30}$ of brain tissues were 11.50%, 10.80%, 10.07% and 7.62%, 7.40%, 7.31%, respectively. It took 30, 120, 90 minutes to produce. The measured TLD results were within ${\pm}7%$ of the planned values. Conclusion: The application of helmet bolus which used Bolx-II during total scalp irradiation not only improves homogeneity and conformity of Clinical Target Volume but also takes short time and the production method is simple. Thus, the helmet bolus which used Bolx-II is considered to be useful for the clinical trials.

• Magazine of the Korean Society of Agricultural Engineers
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• v.31 no.1
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• pp.82-95
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• 1989

This study was carried out for the stability analysis of earth dam by the variation of compaction density. The test samples were taken from five kinds of soil used for banking material and the degree of compaction for this samples were chosen 100, 95, 90, 85, and 80 percent. The stability problems were analysed by the settlement and camber( extra banking) of dam, strength parameter and dam slope, and coefficient of permeability and seapage flow through dam body. The results of the stability analysis of earth dam are as follows. 1. The more the fine particle increases and lower the compaction degree becomes, the lower the preconsolidation load becomes but the compression index becomes higher. 2. Sixty to eighty percent of settlement of dam occurs during the construction period and the settlement ratio after completion of dam is inversly proportional to the degree of compaction. 3. The camber of dam has heigher value in condition that it has more fine particle(N) and heigher dam height(H) with the relation of H= e(aN-bH-e). 4. The cohesion(C) decreases in proportion to compaction degree(D) and fine particle(N) with the relation of C= aD+ bN-c, but the internal friction angle is almost constant regardless of change of degree of compaction. 5. In fine soil, strength parameter from triaxial compression test is smaller than that from direct shear test but, they are almost same in coarse soil regardless of the test method. 6. The safety factor of the dam slope generally decreases in proportion to cohesion and degree of compaction but, in case of coarse soil, it is less related to the degree of compaction and is mainly afected by internal friction angle. 7. Soil permeability(K) decreases by the increases of the degree of compaction and fine particle with relation of K=e(a-bl)-cN) 8. The more compaction thickness is, the less vertical permeability (Kv) is but the more h6rzontal permeability (KH) is, and ratio of Kv versus KH is largest in range from 85 to 90 percent of degree of corn paction. 9. With the compaction more than 85 percent and coefficient of permeability less than ${\alpha}$X 10-$^3$cm/sec, the earth dam is generally safe from the piping action.

• Restorative Dentistry and Endodontics
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• v.38 no.3
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• pp.146-153
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• 2013

Objectives: Aluminum step wedge (ASW) equivalent radiodensity (eRD) has been used to quantify restorative material's radiodensity. The aim of this study was to evaluate the effects of image acquisition control (IAC) of a digital X-ray system on the radiodensity quantification under different exposure time settings. Materials and Methods: Three 1-mm thick restorative material samples with various opacities were prepared. Samples were radiographed alongside an ASW using one of three digital radiographic modes (linear mapping (L), nonlinear mapping (N), and nonlinear mapping and automatic exposure control activated (E)) under 3 exposure time settings (underexposure, normal-exposure, and overexposure). The ASW eRD of restorative materials, attenuation coefficients and contrasts of ASW, and the correlation coefficient of linear relationship between logarithms of gray-scale value and thicknesses of ASW were compared under 9 conditions. Results: The ASW eRD measurements of restorative materials by three digital radiographic modes were statistically different (p = 0.049) but clinically similar. The relationship between logarithms of background corrected grey scale value and thickness of ASW was highly linear but attenuation coefficients and contrasts varied significantly among 3 radiographic modes. Varying exposure times did not affect ASW eRD significantly. Conclusions: Even though different digital radiographic modes induced large variation on attenuation of coefficient and contrast of ASW, E mode improved diagnostic quality of the image significantly under the underexposure condition by improving contrasts, while maintaining ASW eRDs of restorative materials similar. Under the condition of this study, underexposure time may be acceptable clinically with digital X-ray system using automatic gain control that reduces radiation exposure for patient.

• Journal of the Korean Society of Costume
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• v.61 no.1
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• pp.69-83
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• 2011

This study applied cartoon-like simple and implicit symbol of Keith Haring works to tubular jacquard knit, designed woman casual knit wear with fun, explicit and activities using fluorescent yarns with explicit features. This study aimed to propose the directions for new market pioneering that meets the emotional requirements of modern people by raising the level of utilization and expression area of knit fashion, and to present the constructive directions for high value-added knit wear by designing highly effective knit wear. Methods of this study examined the lifetime and artistic background of Keith Haring and collected his works through searching of internet, scholastic publications or thesis. Formative types and colors of works collected were analyzed and classified according to characteristic standards of Haring and characteristic formativeness and color of works were extracted. The result of this study is as shown below: First, the feature of his works can be summarized into motif that has symbolic and implicit cartoon-like lines including narratives as well as enormous number of works. Such feature is very suitable for variation and recombination in realization of design and has unlimited potentials for development. Second, image colors can be extracted such as black and white, original color and fluorescent paints, which reflects the intention of artist who put focus on communication with the public. Such color feature is very suitable for design motif that has explicitness of reflecting the intention of artist through use of special fluorescent yarn. Third, I made it as reversible wear that has effects of increasing or decreasing the explicitness according to color area ratio using the feature of textures allowing use of both sides as well as form stability of tubular jacquard. Fourth, by adjusting the thickness of fabric with controlling of ply in fabric using poly yarn and wool union yarn, I could obtain good results of study in terms of technique that can express various materials with embossed dynamic effects of unevenness on flat surface.

• International journal of advanced smart convergence
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• v.4 no.1
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• pp.145-153
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• 2015

Friction Stir Welding (FSW) is a solid state welding that could successfully weld the difficult-to-weldmaterials such as an aluminum alloy. In this welding process, the stirrer of the welding tool is one of the important factors for producing the perfect sound joint that indicates the higher joint strength. So, this report aims to apply the friction stir welding using various stirrer geometries to weld the AA6063-T1 aluminum alloy butt joint, investigates the mechanical properties of the joint and then compares the mechanical properties with the microstructure of the joint. An experiment was started by applying the friction stir welding process to weld a 6.3 mm thickness of AA6063-T1 aluminum alloy butt joint. A study of the stirrer geometries effect such as a cylindrical geometry, a cone geometry, a left screw geometry and a right screw geometry at a rotational speed of 2000 rpm and a welding speed of 50-200 mm/min was performed. The mechanical properties such as a tensile strength and a hardness of the joint were also investigated and compared with the microstructure of the joint. The results are as follows. A variation of FSW Stirrer shape directly affected the quality AA6063-T1 aluminum alloy butt joint. A cylindrical stirrer shape and a cone stirrer shape produced the void defect at the bottom part of the weld metal and initiated the failure of the joint when the joint was subjected to the load during the tensile test. Left and right screw stirrer shapes gave the sound joint with no void defect in the weld metal and affected to increase the joint strength that was higher than that of the aluminum base metal.