• Journal of the Korean Solar Energy Society
• /
• v.30 no.3
• /
• pp.55-64
• /
• 2010

The study has conducted a research on the main shape of domestic multi-family residential buildings. The four arrangements were selected after the research and each of them was analyzed for daylight, view and natural ventilation according to the different pitch of buildings. Based on the results from the analysis, the optimum pitch of buildings for each of the arrangements are as follows. With looking at the outcomes from the analysis on changes in residential environment by the pitch of building buildings in the four arrangements, it was figured out that it would be the best if the distance is more than 1.0H for Case_1. For Case_2, it should be more than 0.9H and for Case_3, it has to be 1.0H or more. Last but not least, it seems to be superb if the distance is more than 0.9H for Case_4.

• Journal of the Institute of Convergence Signal Processing
• /
• v.10 no.2
• /
• pp.127-131
• /
• 2009

In the digital waveguide theory, traveling waves are represented by general solution to the wave equation that is second-order linear partial differential equation. The movement of these waves can be implemented using only delay lines. An unit delay in the general digital waveguide describes a sampling time interval. However, in the space-based digital waveguide the unit delay implies the spatial sampling distance. In consideration of these differences between two models, it is known that the space-based digital waveguide model is adequate to synthesize pitch-shifted sounds such as vibrato because the propagation distance can be directly control. In this paper, the time-based digital waveguide model which also synthesizes pitch-shifted sounds is proposed and compared with space-based digital waveguide.

• Structural Engineering and Mechanics
• /
• v.49 no.3
• /
• pp.311-327
• /
• 2014

The safety relating to leakage of water and pitch instability of ship chambers of the full balanced hoist vertical shiplifts has been the focus of adoption of the type of vertical shiplifts. This paper aims to remove the doubts through theoretical and engineering researches. The leakage and pitch stability of ship chambers of full balanced hoist vertical ship lifts are investigated on the basis of theoretical analysis and exploration of engineering measures. Regarding the issue of leakage of ship chambers, a mathematical model on leaking process is built and corresponding formula and coping measures are obtained which can be applied in control program of ship lifts by linking with monitoring. The concept of safety grade is put forward to seek the best technical and economic index and the corresponding technical measures are for different grades of ship lift is suggested. For the issue of pitch instability, a methodology of combining theoretical deduction and summary of achievements of design and operation of the type of the full balanced hoist shiplifts is adopted, and the formula for design about pitch stability of ship chambers is derived.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.33 no.12
• /
• pp.1427-1432
• /
• 2009

The pitch motion of a generic gravity gradient satellite is investigated in terms of chaos. The Melnikov method is used for detecting the onset of chaotic behavior of the pitch motion of a gravity gradient satellite. The Melnikov method determines the distance between stable and unstable manifolds of a perturbed system. When stable and unstable manifolds transverse on the Poincare section, the resulting motion can be chaotic. The Melnikov analysis indicates that the pitch dynamics of a generic gravity gradient satellite can be chaotic when the orbit eccentricity is small.

• Korean Journal of Applied Biomechanics
• /
• v.17 no.2
• /
• pp.177-185
• /
• 2007

Even though there were no clear definitions of the short game and short game distance, short game capability is crucial for a good golf score. Generally, chip shot and pitch shot are regarded as two principal components of the short game. Chip shot is a short, low trajectory shot played to the green or from trouble back into play. Pitch shot is a high trajectory shot of short length. Biomechanical studies were conducted usually to analyze full swing and putting motions. The purpose of the study was to reveal the kinematical differences between professional golfers' 30 yard $53^{\circ}wedge$ chip shot and $56^{\circ}wedge$ pitch shot motions. Fifteen male professional golfers were recruited for the study. Kinematical data were collected by the 60 Hz three-dimensional motion analysis system. Statistical comparisons were made by paired t-test, ANOVA, and Duncan of the SPSS 12.0K with the $\alpha$ value of .05. Results show that both the left hand and the ball were placed left of the center of the left and right foot at address. The left hand position of the chip shot was significantly left side of that of the pitch shot. But the ball position of the pitch shot was significantly right side of that of the chip shot. All body segments aligned to the left of the target line, open, at address. Except shoulder, there were no significant pelvis, knee, and feet alignment differences between chip shot and pitch shot. These differences at address seem for the ball height control. Pitch shot swing motions(the shoulder and pelvis rotation and the club head travel distance) were significantly bigger than those of the chip shot. Club head velocity of the pitch shot was significantly faster than that of the chip shot at the moment of impact. This was for the same shot length control with different lofted clubs. Swing motion differences seem mainly caused by the same shot length control with different ball height control.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2000.11a
• /
• pp.771-774
• /
• 2000

Coiling processes of filaments need precise work and standardization. It is important to maintain equal pitch of filaments. Uniform pitch of filaments is one of the dominant elements of life time and efficiency of bulbs. First coiling process of filament wires is modeled by nonlinear contact problem between filaments and mandrel. Analysis of coiling process using finite element method is conducted to consider manufacturing parameters and pitch distance is calculated under the given conditions. Also image detecting system is developed to inspect uniformity of pitch. This system will be used to inspect quality of filaments during coiling processes.

• Journal of the Society of Naval Architects of Korea
• /
• v.49 no.5
• /
• pp.410-415
• /
• 2012

An experimental study is carried out to investigate the near-wake characteristics of a NACA 0018 foil with a flat plate. Two-frame grey-level cross correlation PIV method is used to measure the local flow characteristic around a pitch damping foil to control the vertical motion of high speed crafts in a circulating water channel. The analysis also includes angles of attack 10 and 20 degrees respectively. Reynolds number $Re{\fallingdotseq}3.5{\times}10^4$ based on the chord length(C=100mm) of NACA0018 has been applied during the whole experiments. The distance between the foil and the flat plate is D/C=0.5, 1.0 and 1.5 respectively. The channel effect according as the distance between the foil and the flat plate has a close relation with the velocity distributions around the foil. In the wake of 20-degree of attack, the complex turbulent flow and a thick boundary layer are formed due to the processes of vortex generation and dissipation.

• Current Optics and Photonics
• /
• v.5 no.5
• /
• pp.500-505
• /
• 2021

We demonstrated a wide-fan-angle flat-top irradiance pattern with a very narrow linewidth by using an aspheric lens and a long-pitch reflective diffraction grating. First, we numerically designed a diffraction-based linear beam homogenizer. The structure of the Al diffraction grating with an isosceles triangular shape was optimized with 0.1-mm pitch, 35.5° slope angle, and 0.02-mm radius of the rounding top. According to the numerical results, the linear uniformity of the irradiance was more sensitive to the working distance than to the shape of the Al grating. The designed Al grating reflector was fabricated by using a conventional mold injection and an Al coating process. A uniform linear irradiance of 405-nm laser diode with a 100-mm flat-top length and 0.176-mm linewidth was experimentally demonstrated at 140-mm working distance. We believe that our proposed linear beam homogenizer can be used in various potential applications at a precise inspection system such as three-dimensional morphology scanner with line lasers.

• Journal of Advanced Navigation Technology
• /
• v.20 no.3
• /
• pp.246-251
• /
• 2016

This paper has optimized WPT (wireless power transfer) antenna, and compared EM (electromagnetic) simulation result with measurement for the magnetic resonant type standard of A4WP (alliance for wireless power) using 6.78MHz frequency and 1m distance. Power transmission distance is affected by various factors such as system shape, antenna size, and resonator coil pitch etc, which were confirmed by the EM simulation. By simulation an optimized WPT antenna was designed for a fixed distance, and the transmission loss ${\mid}S_{21}{\mid}$ has been calculated with changing distance. Measurement was carried for the fabricated antenna, and the measured transmission loss is 1.5dB with 70% efficiency at maximum 1.3m distance compared to the simulated loss of 1.6dB with 69% efficiency

• Tunnel and Underground Space
• /
• v.4 no.3
• /
• pp.256-260
• /
• 1994

HLW canister array was designed by FLLSSM program, considering the thermal concentration. Rock properties were chosen as those of granite, the most possible bedrock for the repository in Korea. It was shown that repository area and excavation volumes can be determined by the pitch or distance between canisters. Pitch can be reduced to 0.6 m assuming the tolerance temperature as 200$^{\circ}C$. Thermal concentration was reduced as storage time for cooling the canister passed. After 10 years of storage the thermal problems seemed to be negligible.