• Structural Engineering and Mechanics
• /
• v.87 no.5
• /
• pp.431-450
• /
• 2023

In this study, it is intended to perform nonlinear time-history analyses of nuclear power plant structures (NPP) under near-fault earthquakes showing directivity pulse and fling-step characteristics. Simulation procedures based on cycloidal pulse and far-fault ground motions are also used to simulate near-fault motions showing forward-directivity and fling-step characteristics and the structural responses are compared with those of the recorded near-fault ground motions. Because it is aimed to determine specifically the pulse type characteristics of near-fault ground motions on NPPs, all the ground motions are normalized to have a PGA of 0.3 g. Depending on the obtained results it can be underlined that although near-fault ground motion has the potential to cause damage mostly on structural systems having larger periods, it may also have noticeable effects on the responses of rigid structures, like NPP containment buildings. On the other hand, simulated near-fault motions can help us to get an insight into the near-fault mechanism as well as an approximate visualization of the structural responses under near-fault earthquakes.

• Journal of the Korea Fashion and Costume Design Association
• /
• v.24 no.4
• /
• pp.57-72
• /
• 2022

This study categorized and analyzed the body types of adult women in their 20s and 30s using 3D human measurement data from the 8th Size Korea, and intended to construct body shape and dimension data necessary for modeling Korean standard avatars. Data analysis considered data from 1302 adult women in their 20s and 30s, and a total of 49 index values, drop values, and angle items were subjected to factor analysis and one-way ANOVA to categorize the body type, and Duncan test to post-verify significant differences by type. As a result of conducting factor analysis, 13 factors were extracted and were categorized into 4 body types. Type 1 is short in the upper torso, long in the lower torso, long in the arms and legs, and has a upright body shape and sagging shoulder. Type 2 is short in the torso, arms and legs, and has large torso flexion and lower body circumference. Type 3 has abdominal obesity with small torso flexion and lower body circumference. Type 4 is a small body bending forward type. For the distribution of body types by age among those in their 20s and 30s, the highest appearance rate was Type 1 and was therefore selected as the represntative body type. The body type information of this study will be used as basic data for developing standard avatars.

• The Journal of the Acoustical Society of Korea
• /
• v.37 no.5
• /
• pp.285-291
• /
• 2018

In the present study, flow characteristics and wind noises around the sunroof opening are analyzed variation with panoramic sunroof deflector angle. A mesh deflector is attached to reduce wind noise while a car is driving with the panoramic sunroof opening. A new forward inclined type deflector was invented to improve wind noise. The effect of this new concept of mesh deflector on the open-panoramic flow characteristics and wind noises were studied with CAT (Computer Aided Test) and wind tunnel test, which shows the reduction of open-panoramic wind noises such as sunroof buffeting, sunroof booming, and turbulent noise. Therefore, the forward inclined type deflector can efficiently improve wind noise with the same production cost.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.14 no.4
• /
• pp.1561-1567
• /
• 2013

This paper is regarding the helicopter flight control law design for the handling quality performance. MIL-F-83300 and ADS-33E specification is used of the helicopter flight handling quality and to meet these requirements, ACAH type controller is required. This paper described the ACAH type controller design and performance evaluations. Helicopter dynamics first developed as nonlinear dynamics including rotor dynamics and then linear model was extracted from hovering to forward flight mode using trim condition. Control law used the model following to meet the handling qualities, the simple inverse model as feed forward gain, decoupling logic and phase model to decouple the axes, and linear model to calculate the coefficients. Handling quality evaluation used the matlab based Conduit tool and verified that Level 1 requirement is satisfied.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.60 no.1
• /
• pp.205-213
• /
• 2011

The Long Term Evolution (LTE) system is designed to provide a high quality data service for fast moving mobile users. It is based on the Orthogonal Frequency Division Multiplexing (OFDM) and relies its channel estimation on the training samples which are systematically built within the transmitting data. Either a preamble or a lattice type is used for the distribution of training samples and the latter suits better for the multipath fading channel environment whose channel frequency response (CFR) fluctuates rapidly with time. In the lattice-type structure, the estimation of the CFR makes use of the least squares estimate (LSE) for each pilot samples, followed by an interpolation both in time-and in frequency-domain to fill up the channel estimates for subcarriers corresponding to data samples. All interpolation schemes should rely on the pilot estimates only, and thus, their performances are bounded by the quality of pilot estimates. However, the additive noise give rise to high fluctuation on the pilot estimates, especially in a communication environment with low signal-to-noise ratio. These high fluctuations could be monitored in the alternating high values of the first forward differences (FFD) between pilot estimates. In this paper, we analyzed statistically those FFD values and propose a postprocessing algorithm to suppress high fluctuations in the noisy pilot estimates. The proposed method is based on a localized adaptive moving-average filtering. The performance of the proposed technique is verified on a multipath environment suggested on a 3GPP LTE specification. It is shown that the mean-squared error (MSE) between the actual CFR and pilot estimates could be reduced up to 68% from the noisy pilot estimates.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.10 no.4
• /
• pp.380-387
• /
• 2005

We report the performance of an open-frame type low-voltage high-current DC-DC converter module developed using an active clamp forward converter circuit and single ended rectifier. The converter module is designed with the specifications of an 3.3V output voltage, 30A output current, 100W output power and 36-75V input voltage. The synchronous rectifier is used to reduce the conduction loss at high current level and constant current control using precision PCB resistance is adapted to enhance the over current protection function in the system configuration. A prototype converter module is successfully implemented within 8mm height and quarter brick size (58x37mm) and recorded an $95W/in^3$ power density, 90.6$\%$ efficiency and 0.07$\%$ voltage regulation for the entire Input voltage range, thereby demonstrating its application potentials to future telecommunication electronics.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.14 no.1
• /
• pp.8-14
• /
• 2009

A lamp which is currently employed to LCD(Liquid Crystal Display) Backlight is almost CCFL(Cold Cathod Fluorescent Lamp) and EEFL(External Electrode Fluorescent Lamp). However, the use of these lamps is being restricted as RoHS(the Restriction of the use of certain Hazardous Substances in electrical and electronic equipment) regulation is gradually reinforced. According to this situation, the manufacturing of a lamp which doesn't use mercury is unescapable. Moreover, LCD TV has a defect which take place Motion Blur phenomenon due to response time of LC(Liquid Crystal), and Hold-type characteristic which only exists in LCD differently to CRT, PDP. In this paper, an inverter is proposed to drive a plane light source lamp which is not containing mercury. Driving circuit of proposed inverter is simple because the number of semiconductor device and magnetic device is reduced by using forward topology. Also, Motion Blur phenomenon is decreased by dividing the plane light source lamp to six block along vertical direction, and scanning. Finally, we proved usefulness of proposed inverter through experiment.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.34 no.6A
• /
• pp.468-475
• /
• 2009

In OFDM-based Full Duplex Relays (FDR) with Decode and Forward (DF) scheme, an interference cancellation technique in the frequency domain is more efficient than the one in the time domain. However, an Inter-Symbol Interference (ISI) and Inter-Carrier Interference (ICI) may occur due to the timing mismatch between the feedback interference signal and the desired signal from Base Station (BS) when the feedback interference cancellation and demodulation are performed in the frequency domain. In this paper, the effects of timing mismatch on the synchronous type and asynchronous type of OFDM-based FDR are analyzed for uplink and downlink cases. Then, synchronization procedure and methods for reducing ISI and ICI in OFDM-based FDR with frequency-domain feedback interference canceller are proposed and verified by computer simulation.

• International Journal of Costume and Fashion
• /
• v.3
• /
• pp.13-24
• /
• 2003

The purpose of this study was to examine the changes brought by the upper body form using a three-dimensional human body measurement the gypsum method. The developed plane figure was constructed using paper replica to analyze the dimensional shape of the upper torso and to be able to design clothes suitable for elderly women's physical characteristics. The characteristics are analyzed and compared with existing patterns in order to extract the components for the pattern design. The examination was carried out based on the developed plane figures of upper body surface replicas. Type 1, the bent-forward body form, has a wide gap on the shoulder. In Type 2, the gap of waist line was wide at angulus scapulae point. Type 3 was the thin body form, and the girth of the chest, front interscye breadth and back interscye breadth were more level with one another, compared to the other types. In Type 4, the bent-backward body form, there was a wide gap on front shoulder. Comparison with the developed plane figure and existed pattern, items revealed differences in significance included the front and back interscye width between the measured values of the existed patterns and the developed plane figure. Therefore, the basic components of basic bodice pattern for old women were determined in the up-bust circumference and length of the back.

• Journal of Industrial Technology
• /
• v.26 no.B
• /
• pp.63-71
• /
• 2006

The concerned object of the construction industry is environment. It is one of the main purposes of today's construction that human can live reasonably in nature. This study is about the fish-road connecting hydraulic structure in the river with nature. Chapter 2, starting with the general investigation about fish-road and helps comprehension for relatively general fish-road such as necessity, establishment purpose, history, study example, relating domestic law, design condition, consideration and form of fish-road. Chapter 3, containing the present condition of fish-road facilities in Gangwon-Do and thoughts of the problems and general countermeasures of existing fish-road. Chapter 4, Having Examined compatibility by amount of flowing water through hydraulic model test in the Ice harbor I-type model. chapter 5, Analyzation and arrangement to efficient establishment plan of fish-road and the result of the hydraulic model experiment to be beaconed a little in forward fish-road study. In the hydraulic model test result, when we suppose establishment of 1~3 in slope of 1/20, could know that applicable drought flow of the river is $0.06{\sim}3.0m^3/sec$ in case of Ice harbor I-type which transforming Ice harbor that was invented as studying project of the Ministry of Environment.