• Journal of the Korean Society of Costume
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• v.57 no.5 s.114
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• pp.1-11
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• 2007

The purpose of this study was to analyze and minimize structural error between sample knitting and actual knitting in weft knitting apparel. Basic stitches used in this study were plain stitch, $0{\times}0$ rib stitch, $1{\times}1$ rib stitch, $2{\times}2$ rib stitch, Milan rib stitch. They were knitted into two different gauges(7 and 12 gauge) and 6 different sample sizes by computer program. The weight, length and width of these 5 basic knitting stitches were measured and their changes according to gauge, stitch and knitting were calculated and analyzed. The results were as follows; The weight of $0{\times}0$ rib stitch was the largest, followed by Milan rib stitch, $2{\times}2$ rib stitch, plain stitch and $1{\times}1$ rib stitch. As the density of stitch per unit area increases, the weight increases. The length of $0{\times}0$ rib stitch was the largest, followed by plain stitch, $2{\times}2$ rib stitch, $1{\times}1$ rib stitch and Milan stitch in both 7 and 12 gauge. As the number of course increases, the length increases accordingly. However, its increase ratio shows higher than that of number of course. It means that the reduction in number of course is needed to get aimed length. The width of Milan rib stitch was the largest, followed by $0{\times}0$ rib stitch, plain stitch, $2{\times}2$ rib stitch, $1{\times}1$ rib stitch in 7 gauge. In 12 gauge, Milan stitch, plain stitch and $0{\times}0$ rib stitch were the highest, followed by $2{\times}2$ rib stitch and $1{\times}1$ rib stitch. It showed that the change in shape of stitch influenced on the width more than the length of stitch.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.10a
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• pp.281-285
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• 2001

According to standard procedures as defined in the users handbook for sea level data processes, I was compared to Topex/poseidon sea level data from the first 350days of mission and Tide Gauge sea level data from the Amsterdam- Crozet- Kerguelen region in the South Indian Ocean. The comparison improves significantly when many factors for the corrections were removed, then only the aliased oceanic tidal energy is removed by oceanic tide model in this period. Making the corrections and smoothing the sea level data over 60km along-track segments and the Tide Gauge sea level data for the time series results in the digital correlation and RMS difference between the two data of c=-0.12 and rms=11.4cm, c=0.55 and rms=5.38cm, and c=0.83 and rms=2.83cm for the Amsterdam, Crozet and Kerguelen plateau, respectively. It was also found that the Kerguelen plateau has a comparisons due to propagating signals(the baroclinic Rossby wave with velocity of -3.9~-4.2cm/sec, period of 167days and amplitude of 10cm) that introduce temporal lags($\tau$=10~30days) between the altimeter and tide gauge time series. The conclusion is that on timescales longer than about 10days the RMS sea level errors are less than or of the order of several centimeters and are mainly due to the effects of currents rather than the effects of sterics(water temperature, density) and winds.

• Proceedings of the Korean Fiber Society Conference
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• 1991.06b
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• pp.75-75
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• 1991

• Journal of Korea Water Resources Association
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• v.42 no.6
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• pp.493-503
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• 2009

Estimation of the mean-field bias of radar rainfall is to determine the difference between the areal means of radar and rain gauge rainfall, where the rain gauge rainfall is assumed to be the truth. To exactly determine this bias, the variance of the difference between two observations must be small enough, thus, enough number of observations is indispensible. So, the problem becomes to determine the number of rain gauges to satisfy the level of variance of the difference between two observations. Especially, this study focuses on the case when the rain gauges are disproportionate spatially. This is the problem for the Ganghwa rain radar for the observation of rainfall within the Imjin river basin and the same problem also occurs when a radar is located in between land and ocean. This study considered the Imjin river basin, and compared two cases when rain gauges are available only within the downstream part, about one third of the whole basin, and over the whole basin. Based on the results derived, the rain gauge density within the downstream part of the Imjin river basin was proposed to secure the same accuracy obtained when the rain gauges are available over the whole Imjin river basin.

• Journal of Radiation Protection and Research
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• v.22 no.4
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• pp.289-298
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• 1997

Time-consuming experiments have been required in the development of neutron moisture gauge to induce a relation between the water content in soil and the neutron counts. Applying a monte carlo computer code to simulate the experiments of neutron moisture gauging may contribute to reduce time and efforts for experiments and produce a calibration equation which is more applicable to soil in general. In this study MCNP4A, a monte carlo computer code, was employed to simulate soil experiments and the simulated results were compared with experimental ones. The comparative study showed that MCNP4A is applicable to simulate the experiments and calibration equation can be obtained through simulations. Effects of dry density changes were also studied.

• Atmosphere
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• v.25 no.2
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• pp.283-294
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• 2015

For urban flash flood simulation, we need the higher resolution radar rainfall than radar rainfall of KMA, which has 10 min time and 1km spatial resolution, because the area of subbasins is almost below $1km^2$. Moreover, we have to secure the high quantitative accuracy for considering the urban hydrological model that is sensitive to rainfall input. In this study, we developed the quantitative precipitation estimation (QPE), which has 250 m spatial resolution and high accuracy using KMA AWS and SK Planet stations with Mt. Gwangdeok radar data in Seoul area. As the results, the rainfall field using KMA AWS (QPE1) is showed high smoothing effect and the rainfall field using Mt. Gwangdeok radar is lower estimated than other rainfall fields. The rainfall field using KMA AWS and SK Planet (QPE2) and conditional merged rainfall field (QPE4) has high quantitative accuracy. In addition, they have small smoothed area and well displayed the spatial variation of rainfall distribution. In particular, the quantitative accuracy of QPE4 is slightly less than QPE2, but it has been simulated well the non-homogeneity of the spatial distribution of rainfall.

• Structural Monitoring and Maintenance
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• v.4 no.1
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• pp.1-15
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• 2017

Installation of sensors networks for continuous in-service monitoring of structures and their efficiency conditions is a current research trend of paramount interest. On-line monitoring systems could be strategically useful for road infrastructures, which are expected to perform efficiently and be self-diagnostic, also in emergency scenarios. This work researches damage detection in composite concrete-steel structures that are typical for highway overpasses and bridges. The techniques herein proposed assume that typical damage in the deck occurs in form of delamination and cracking, and that it affects the peak power spectral density of dynamic curvature. The investigation is performed by combining results of measurements collected by long-gauge fiber optic strain sensors installed on monitored structure and a statistic approach. A finite element model has been also prepared and validated for deepening peculiar aspects of the investigation and the availability of the method. The proposed method for real time applications is able to detect a documented unusual behavior (e.g., damage or deterioration) through long-gauge fiber optic strain sensors measurements and a probabilistic study of the dynamic curvature power spectral density.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.04a
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• pp.138-143
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• 2000

In order to maintain the faith and accuracy with precision of machinery, it is recently required the precise comprehension about approach which is appeared in the contact area between two bodies, because approach affects the static stiffness and dynamic characteristic of contact area. This study applied H. Hertz's circle contact area theory as much lower measuring force. It is measured approach influenced by various factors which were concerned with contact errors like material, form of two bodies, using calibration tester. As a result, the following conclusion can be obtained. 1) The approach appears greatly in order of carbon steel(SM20C), aluminum(A601-T6) and high density polyethylene(5305E) 2) The approach appears in order of concave, disc, convex form, in the ration of contact area size by the difference of curvature.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.2
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• pp.200-206
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• 1992

The effect of fiber diameter and gauge length on pull-out test for the interfacial properties in fiber reinforced resin composites have been investigated and these results have been arranged as statistical analysis. The fiber and matrix resins used for this study were stainless steel fiber (SUS316) and carbon fiber (high strength type), epoxy and high density polyethylene resin. From this study, it has been found that shear strength are constant regardless of gauge length of pull-out test and coefficient of variation depend on fiber diameter. In addition, it has been found that the interfacial shear strength decreased with the increasing fiber diameter, and in all case, Weibull parameter (m) has approximately 1.2/C.O.V.

• Nuclear Engineering and Technology
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• v.54 no.11
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• pp.4236-4243
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• 2022

An industrial nuclear technique based on the use of an X-ray profiler was implemented to estimate the densities or concentrations of sediments present in an Atlantic maritime zone in the areas subjected to dredging under the governance of the Panama Canal Authority (ACP). The sediment profiles show in most areas there is a concentration of between 1.00-1.15 g/cm³ except for one area in particular, the density starts at 1.20 g/cm³ and even reaches values greater than 1.50 g/cm³; therefore, an already consolidated sediment is present, which, depending on the depth found. Values of 1.265 g/cm³, 1.297 g/cm³, 1.185 g/cm³ obtained by ACP previous studies are within the range of 1.20-1.30 g/cm³ measured with the nucleonic gauge. However, it should be noted that during the tests with the X ray profiler, sediment densities values greater than the aforementioned limit were also obtained that varying according at depths close to 12 m and 18 m with values reached up to 1.513 g/cm³ and 1.60 g/cm³, respectively. This demonstrates that sediment accumulation depends on depth. This nucleonic gauge is feasible technique for the study of the sedimentation phenomenon in channel basins and even in other projects nationwide.