• The Journal of Asian Finance, Economics and Business
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• v.5 no.4
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• pp.95-100
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• 2018

The study investigates the factors that affect Kyrgyzstan's bilateral trade flows with its main trading partners and attempts to predict trade potential for Kyrgyzstan. Using panel data, the gravity model is applied to estimate Kyrgyzstan's trade from 2000 to 2016 for its 35 main trading partners. The coefficients derived from the gravity-model estimation are then used to predict trade potential for Kyrgyzstan. Results proved to be successful and explained 63% of the fluctuations in Kyrgyzstan's trade. According to the results, Kyrgyzstan's and its partners' GDP have a positive effect on trade, while distance and partners' population prove to have a negative effect. Predicted trade potential reveals that neighboring countries (China, Kazakhstan, Uzbekistan, and Tajikistan) and Russia still have a significant trade potential. Kyrgyzstan, being a less developed economy, even by Central Asia standards, can only achieve its goals of reducing poverty and becoming more developed by increasing its overall trade with the rest of the world. Therefore, it is essential to study the main determinants of Kyrgyzstan's bilateral trade. In this way, we can help policy makers formulate policies to expand Kyrgyzstan's trade. This study is the first attempt to apply to the gravity model to Kyrgyzstan in an attempt to predict trade potential.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.04a
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• pp.533-538
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• 2000

In R.C. flat slab system, a brittle punching failure is a very fatal problem. But there is no generally well-defined answer to the problem and there are wide differences in current practical design codes. therefore, in this study, the factors affecting to punching failure mechanism have been studied to find out the punching shear behavior in R.C. flat slabs by comparing other investigations and practical design codes. Therefore, In this study, the factors affecting to punching failure mechanism have been studied to find out the punching shear behavior in R.C. flat slabs by comparing other investigations and practical design codes. The conclusions in this study are summarized as follows; 1) The factors affecting to punching shear are concrete strength ($f_\alpha$), ratio of column side length to slab depth (c/d), ratio of distance from column center to radial contraflexure (l/d), yield strength of steel ($f_y$), flexural reinforcement ratio ($\rho$) and size effects. 2) It is shown that th use of $\surd{f_{ck}}$in applying($f_\alpha$ to punching shear strength estimation may be more sensitive in high concrete strength. 3) The effects of l/d, ($f_y$, size are no clear in the punching failure mechanism, so in the future, it should be investigated with the effects of various composed load.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2012.07a
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• pp.87-90
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• 2012

본 논문에서는 깊이 변화에 강인한 스테레오 비디오의 변이 탐색 범위 추정 방법을 제안한다. 정확한 스테레오 비디오의 변이 탐색 범위는 3D 영상 분야에서 다양한 응용으로 사용되는 변이 지도를 보다 정확하게 추정하는데 도움이 된다. 기존의 변이 탐색 범위 추정 방법은 인접한 프레임 간의 변이 히스토그램의 유사도를 이용함으로써 보다 안정적인 변이 탐색 범위를 추정할 수 있었지만, 시간의 흐름에 따라 깊이가 변하는 부분에서는 상당히 취약한 문제점을 가지고 있다. 이에 본 논문에서는 기존 방법의 이러한 문제점을 개선한 새로운 방법을 제안한다. 제안하는 방법은 변이 히스토그램의 유사도뿐만 아니라 프레임 간의 시간적 유사도를 고려하며, 비디오의 장면 전환에 의한 급격한 깊이 변화 또한 고려한다. 이에 추가적으로 변이 히스토그램의 유사도를 계산하기 위해 기존의 방법과는 달리 히스토그램 확산 거리를 이용하였으며, 서로 다른 개수의 대응점을 가지고 있는 프레임간의 변이 히스토그램이 대응점의 개수에 영향을 받지 않고 균일한 중요도를 갖도록 하였다. 실험 결과로 기존 방법과 제안한 방법의 변이 탐색 범위 추정 결과를 비교하였으며, 비교한 결과는 제안한 방법이 기존 방법에 비해 스테레오 비디오의 깊이 변화에 강인함을 보여준다.

• The Journal of Korea Robotics Society
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• v.9 no.1
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• pp.39-47
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• 2014

Odometry using wheel encoders is one of the fundamental techniques for the pose estimation of wheeled mobile robots. However, odometry has a drawback that the position errors are accumulated when the travel distance increases. Therefore, position errors are required to be reduced using appropriate calibration schemes. The UMBmark method is the one of the widely used calibration schemes for two wheel differential drive robots. In UMBmark method, it is assumed that odometry error sources are independent. However, there is coupled effect of odometry error sources. In this paper, a new calibration scheme by considering the coupled effect of error sources is proposed. We also propose the test track design for the proposed calibration scheme. The numerical simulation and experimental results show that the odometry accuracy can be improved by the proposed calibration scheme.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.63-63
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• 2021

Bed shear stress is important variable in river flow analysis. The bed shear stress has an effects on bed erosion, sediment transport, and mean flow characteristics. Quadratic formula to estimate bed shear stress is widely used, 𝜏=𝜌c_fu|u| in which friction coefficient, c_f, needs to be assigned to numerical models. The aim of this study is to estimate Chezy coefficient using bathymetry data measured by ADCP. Bed form geometry variables will be estimated form bed profile, then Chezy coefficient will be determined using estimated bed form geometry variables in order to set friction coefficient to numerical model. From the probability density function obtained from the bathymetry data, Chezy coefficient will be randomly generated since Chezy coefficient is not uniform over the space and it does not depend on spatial variables such as water depth and distance from river bank. Numerical test will be performed to find to demonstrate randomly extracted Chezy coefficient is appropriate. The result of this study is valuable in that the friction coefficient is estimated in consideration of the bed profile, and as a result, uncertainty of the friction coefficient can be reduced.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.1
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• pp.310-315
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• 2017

Although studies evaluating the effects of the blasting vibration on the adjacent structures from various angles have continued, cases of securing the safety of the adjacent buildings and researching the proper blasting method for the field condition by analyzing the vibration waveform of the measuring field while performing the open pit blasting are poor. Therefore, it is necessary to present a remedy for blasting pattern selection through test blasting that is appropriate for field conditions, and is economical and efficient. In this study, open pit blasting work was conducted based on the separation distance applied according to the standard blasting method by test blasting and the vibration regulation standard in the road expansion construction site to measure the blasting vibration value, and the vibration prediction equation by blasting methods was examined using a regression analysis computer program to calculate K, N, and R of the confidence level 95%. By setting the blasting allowed vibration standard of the test blasting target area to 0.3cm/sec, and the charring weight and blasting method by the separation distances according to the blasting vibration estimation equation of the open pit blasting guideline and the blasting vibration estimation equation of the test blasting were compared/analyzed, it was possible to identify the factors that increased the working expenses. In addition, the measurement and analysis of the adjacent structures during open pit blasting and the blasting vibration were performed after selecting the most adjacent structure to the open pit blasting spot to analyze the problems on the test blasting procedure and analysis method in the open pit blasting design/construction guidelines, which appeared in the process of completing open pit blasting construction, and a remedy is presented.

• Spatial Information Research
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• v.11 no.1
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• pp.23-32
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• 2003

TIN is applied in pondage calculation and topography analysis. And much processing time and storage capacity are needed because TIN contains information as elevation, slope and aspect. In the construction of TIN using contour, weed tolerance that is used for the simplification of line is influenced on the sampling distance of contour. The processing time and storage capacity of TIN are calculated in according to the weed tolerance of various size in this research. And we estimated OEMs standard error that is created from TIN to present reasonable weed tolerance and decided the size of weed tolerance that satisfy DEM standard error. We got TINs weed tolerance that satisfy DEM standard error(5m) was 70m and DEMs resolution is 20m as estimation result.

• ETRI Journal
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• v.39 no.4
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• pp.535-545
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• 2017

This paper presents a novel K-band (18 GHz) 16-quadrature amplitude modulation (16-QAM) orthogonal frequency-division multiplexing (OFDM)-based $2{\times}2$ line-of-sight multi-input multi-output communication system. The system can deliver 356 Mbps on a 56 MHz channel. Alignment mismatches, such as amplitude and/or phase mismatches, between the transmitter and receiver antennas were examined through hardware experiments. Hardware experimental results revealed that amplitude mismatch is related to antenna size, antenna beam width, and link distance. The proposed system employs an alignment mismatch compensation method. The open-loop architecture of the proposed compensation method is simple and enables facile construction of communication systems. In a digital modem, 16-QAM OFDM with a 512-point fast Fourier transform and (255, 239) Reed-Solomon forward error correction codecs is used. Experimental results show that a bit error rate of $10^{-5}$ is achieved at a signal-to-noise ratio of approximately 18.0 dB.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.5A
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• pp.409-416
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• 2007

In cellular orthogonal frequency division multiplexing (OFDM) networks, co-channel interference (CCI) leads to severe degradation in the BER performance. To solve this problem, maximum-likelihood estimation (MLE) CCI cancellation scheme has been proposed in the literature. MLE CCI cancellation scheme generates weighted replicas of the transmitted signals where weights represent the estimated channel transfer functions. The replica with the smallest Euclidean distance from the received signal is selected and data are detected. When the received power of the desired and interference signals are nearly the same, the BER performance is degraded. In this paper, we propose a closed-loop power control (PC) scheme capable of detecting the equal received power situation at the mobile station (MS) receiver by using the newly introduced parameter power ratio (PR). When this situation is detected, the MS sends a feedback to the desired base station (BS) which boosts the transmission power in the next frame. At cell edge where signal to interferer ratio (SIR) is considered to have average value between -5 dB and 10 dB, computer simulations show that the proposed CCI cancellation scheme has a gain of 7 dB at 28 Km/h.

• The Journal of the Korea institute of electronic communication sciences
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• v.6 no.1
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• pp.148-156
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• 2011

This paper presents an implementation of autonomous navigation of a mobile robot indoors. It explains methods for map building, localization, obstacle avoidance and path planning. Geometric map is used for localization and path planning. The localization method calculates sensor data based on the map for comparison with the real sensor data. Monte Carlo Localization(MCL) method is adopted for estimation of the robot position. For obstacle avoidance, an artificial potential field generates repulsive and attractive force to the robot. Dijkstra algorithm plans the shortest distance path from a start position to a goal point. The methods integrate into autonomous navigation method and implemented for indoor navigation. The experiments show that the proposed method works well for safe autonomous navigation.