• Journal of Broadcast Engineering
• /
• v.23 no.6
• /
• pp.925-930
• /
• 2018

In this paper, we present a low profile dual-microstripline-fed double 4-arrayed meander monopole antenna with a cross-type element back by separated four-segments mesh-type reflector. The cross-type element and separated four-segments mesh-type reflector leads to enhance radiation patterns and antenna gain characteristics. The measurement value of the proposed antenna show that it has dipole-like radiation pattern characteristics. The experimental peak gain of fabricated antenna is about 2.89 dBi, which presents relatively high gain characteristics for a low profile(small-size) one. This antenna can be applied mobile RFID(radio frequency identification) readers, small medical instruments, broadcasting and home-networking operations, and other low profile high-gain systems.

• Steel and Composite Structures
• /
• v.45 no.5
• /
• pp.665-682
• /
• 2022

In the current study, punching behavior of Reinforced concrete (RC) isolated footings was experimentally and numerically investigated. The experimental program consisted of four half-scale RC isolated footing specimens. The test matrix was proposed to show effect of footing area, reinforcement mesh ratio, adding internal longitudinal reinforcement bars and stirrups on the punching response of RC isolated footings. Footings area varied from 1200×1200 mm2 to 1500×1500 mm2 while the mesh reinforcement ratio was in the range from 0.36 to 0.45%. On the other hand, a 3D non-linear finite element model was constructed using ABAQUS/standard program and verified against the experimental program. The numerical results agreed well with the experimental records. The validated numerical model was used to study effect of concrete compressive strength; longitudinal reinforcement bars ratio and stirrups concentration along one or two directions on the ultimate load, deflection, stiffness and failure patterns of RC isolated footings. Results concluded that adding longitudinal reinforcement bars did not significantly affect the punching response of RC isolated footings even high steel ratios were used. On the contrary, as the stirrups ratio increased, the ultimate load of RC isolated footings increased. Footing with stirrups ratio of 1.5% had ultimate load equal to 1331 kN, 19.6% higher than the bare footing. Moreover, adding stirrups along two directions with lower ratio (0.5 and 0.7%) significantly enhanced the ultimate load of RC isolated footings compared to their counterparts with higher stirrups ratio (1.0 and 1.5%).

• KNOM Review
• /
• v.22 no.3
• /
• pp.25-30
• /
• 2019

For meteorological applications, meaningful results must be derived and provided within time and resource limits. Forecasts through numerous historical data are time-consuming and still have resource limitations in the case of disaster safety-related analyses/predictions such as local typhoon forecasts. Suitable forecasts should be provided without any problems caused by limited physical environmental conditions and when results are to be drawn under time constraints, such as typhoon forecasts and forecast services for flooded areas by road. In this paper, we analyze the application of weather and climate forecasting to provide a suitable forecasting service in both temporal and resource conditions. Through the analysis of execution time according to mesh sizes, it was confirmed that a mesh adjustment can cope with the case of the temporal constraint. In addition, by analyzing the execution time through memory resource control, we confirmed the minimum resource condition that does not affect the performance and the resource usage pattern of the application through the swap and mlock analysis.

• Structural Engineering and Mechanics
• /
• v.90 no.4
• /
• pp.371-390
• /
• 2024

Investigating the impact of openings on the structural behavior of ferrocement I-beams with two distinct types of reinforcing metallic and non-metallic meshes is the primary goal of the current study. Up until failure, eight 250x200x2200 mm reinforced concrete I-beams were tested under flexural loadings. Depending on the kind of meshes used for reinforcement, the beams are split into two series. A control I-beam with no openings and three beams with one, two, and three openings, respectively, are found in each series. The two series are reinforced with three layers of welded steel meshes and two layers of tensar meshes, respectively, in order to maintain a constant reinforcement ratio. Structural parameters of investigated beams, including first crack, ultimate load, deflection, ductility index, energy absorption, strain characteristics, crack pattern, and failure mode were reported. The number of mesh layers, the volume fraction of reinforcement, and the kind of reinforcing materials are the primary factors that vary. This article presents the outcomes of a study that examined the experimental and numerical performance of ferrocement reinforced concrete I-beams with and without openings reinforced with welded steel mesh and tensar mesh separately. Utilizing ANSYS-16.0 software, nonlinear finite element analysis (NLFEA) was applied to illustrate how composite RC I-beams with openings behaved. In addition, a parametric study is conducted to explore the variables that can most significantly impact the mechanical behavior of the proposed model, such as the number of openings. The FE simulations produced an acceptable degree of experimental value estimation, as demonstrated by the obtained experimental and numerical results. It is also noteworthy to demonstrate that the strength gained by specimens without openings reinforced with tensar meshes was, on average, 22% less than that of specimens reinforced with welded steel meshes. For specimens with openings, this value is become on average 10%.

• The Korean Journal of Soil Zoology
• /
• v.4 no.2
• /
• pp.75-80
• /
• 1999

Two years-study with litter bag (mesh size : 0.4 mm, 1.7 m) was carried out from Nov., 1996 to Sept., 1998 to investigate the soil microarthropod community in the process of needle leaf secomposition of Korean pine (Pinus koraiensis) forest in Namsan and Kwangreung, where were supposed to be under different environmental selective pressures. Soil arthropoda collected from litter bags were sorted into suborders or higher taxa. Acari and Collembola were dominant groups, which were 61-68% and 27-35% of total soil arthropod in their numbers, respectively. Among Acari, Oribatida was major group, and Gamasida and Actinedida were minor groups. Abundance of Acari was a little higher in Kwangreng than in Namsan. But there was not significant difference between the arthropod community structure of Namsan and Kwangreng forest. And the different mesh sizes (0.4 mm and 1.7 mm) of litter bags could not make significantly different community structures in the litter bags. One taxon showed different pattern of population dynalics from another. But Oribatida, Gamasida and Collembola showed peak density in July, 1997. All taxa showed lower population densities in cold season i.e. Nov., Jan. and March. There was not significant difference in decomposition rate between Namsan and Kwangreng forest, and between mesh sizes of litter bags. % residual mass of needle leaf was about 40% at 22 months after litter fall.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.41 no.1
• /
• pp.141-152
• /
• 2017

The lumbar disc is one of the first parts of the human body to age. Female discs start to age at twenty and completely age between fifty and sixty. The number of lumbar herniated intervertebral disc patients is increasing rapidly; however, studies on protective inner wear are insufficient. This study develops protective inner wear equipment for bodies. The following were the study methods and procedures. First, the protective design, pattern and making of the inner wear were based on the analysis of collected data. Second, one subject was selected, then human body parts were measured to create the inner protective pattern. The inner pattern was made by the basic size of the subject. The inner protective equipment was made for lumbar disc disease patients after a wearing test and after correcting the pattern. Third, inner protective equipment was thoroughly tested to verify the compatibility of lumbar pads. The following were the study results and observations. First, lumbar pads who had inner protection were easily worn and the design was very ladyish in contrast to other lumbar pads on the market. Second, the pattern was completed by referring to, Lee Hyoung Sook's, torso and her lumbar pad shape. The fabric was mesh (for good ventilation) and poly spandex (for elasticity). Third, lumbar inner protective equipment was verified through a subject assessment and a major assessment. This study showed high scores on appearance and functional satisfaction versus existing disc lumbar pads in the market. This study predicts that new waist protective inner wear can help the female patient's health and social life because it has great functionality and can maintain outer line patterns.

• Journal of the Korean Society of Safety
• /
• v.15 no.2
• /
• pp.1-7
• /
• 2000

This paper presents the approach involving fault detection and diagnosis of gears using pattern recognition and Wavelet transform. It describes result of the comparison between KDI (Kullback Discrimination Information) with the nearest neighbor classification rule as one of pattern recognition methods and Wavelet transform to know a way to detect and diagnosis of gear damages experimentally. To model the damages 1) Normal (no defect), 2) one tooth is worn out, 3) All teeth faces are worn out 4) One tooth is broken. The vibration sensor was attached on the bearing housing. This produced the total time history data that is 20 pieces of each condition. We chose the standard data and measure distance between standard and tested data. In Wavelet transform analysis method, the time series data of magnitude in specified frequency (rotary and mesh frequency) were earned. As a result, the monitoring system using Wavelet transform method and KDI with nearest neighbor classification rule successfully detected and classified the damages from the experimental data.

• Korean Journal of Human Ecology
• /
• v.24 no.6
• /
• pp.875-887
• /
• 2015

The analysis in this work is about costumes among the rhythmic gymnasts in competition, which is intended to develop designs about rhythmic gymnastics costume and provide the basic material from the results. In its research method and range, the general information on rhythmic gymnastics was reviewed in literature and the case analysis was followed about costumes of world high rankers in competition during 2012~2015 seasons. Research showed the following results. First, leotard took a shape of skirt-added one-piece type, where a combination with long tight sleeve, round neck line, and stand-up collar had a relatively higher percentage in design. With regard to a bottom line of skirt, an amorphous type was most common that highlights rhythmical beauty without any particular form. This design exposed shoulders and waists on both sides, expressing the feminine beauty. Second, in color used mainly, white appeared most frequently. In its combination, more than three were employed. Third, transparent mesh was applied as basic, where lace and chiffon were used. Abstract pattern took the highest portion in pattern. Particularly, crystal bead or gradation coloring was used to maximize the visually splendid image, giving an effect of optical illusion as if neckless clothing, choker, bracelet, or glove were worn. Fourth, it appeared that the costume for each event was changed in every season, when only music was substituted but the same earlier costume was put on for the different event.

• Journal of the Korean Society for Precision Engineering
• /
• v.27 no.9
• /
• pp.11-15
• /
• 2010

In this study, to fabricate a low-resistance and high optical transparency electrode film, the following steps were performed: the design and manufacture of electroforming stamp, the fabrication of a thermal roll-imprinted polycarbonate (PC) patterned films, the filled low-resistance Ag paste using doctor blade process on patterned PC films and spin coating by conductive polymers. As a result of PC films imprinted line width of $26.69{\pm}2\;{\mu}m$, channel length of $247.57{\pm}2\;{\mu}m$, and pattern depth of $7.54{\pm}0.2\;{\mu}m$. Ag paste to fill part of the patterned film with conductive polymer coating and then the following parameters were obtained: a sheet resistance of $11.1\;{\Omega}/sq$ optical transparency values at a wavelength of 550 nm was 80.31 %.

• Korean Journal of Computational Design and Engineering
• /
• v.22 no.1
• /
• pp.70-79
• /
• 2017

Weft straightener is an important process to control the final quality of the fabrics. It is needed to calibrate the distorted weft after dyeing process. During various fabric treatment processes, the fabric is almost done with heat treatment through a tenter machine. At this time, weft distortion is occurred with uneven tension distribution. Traditionally, photo sensor is commonly used to detect the weft distortion but it is not applicable for special fabric types such as twill, mesh, combi, etc. In this paper, a new method for detecting the weft distortion using camera is introduced. A new weft straightener simulator is also developed to test the ability of the proposed method. It is shown that the method can be applied for various fabric types.