• Journal of Institute of Control, Robotics and Systems
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• v.20 no.1
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• pp.48-57
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• 2014

It is suggested that the curvature trajectory be used to estimate the real-time moving sound sources and efficiently the robot estimating the sound sources. Since the target points of the real-time moving sound sources change, the mobile robot continuously estimates the changed target points. In such a case, the robot experiences a slip phenomenon due to the abnormal velocity and the changes of the navigating state. By selecting an appropriate curvature and navigating the robot gradually by using it, it is possible to enable the robot to reach the target points without having much trouble. In order to recognize the sound sources in real time, three microphones need to be organized in a straight form. Also, by applying the cross-correlation algorithm to the TDOA base, the signals can be analyzed. By using the analyzed data, the locations of the sound sources can be recognized. Based on such findings, the sound sources can be estimated. Even if the mobile robot is navigated by selecting the gradual curvature based on the changed target points, there could be errors caused by the inertia and the centrifugal force related to the velocity. As a result, it is possible to control the velocity of both wheels of the robot through the velocity PID controller in order to compensate for the slip phenomenon and minimize the estimated errors. In order to examine whether the suggested curvature trajectory is appropriate for estimating the sound sources, two mobile robots are arranged to carry out an actual experiment. The first robot is moved by discharging the sound sources, while the second robot recognizes and estimates the locations of the discharged sound sources in real time.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.39 no.1
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• pp.1-8
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• 2002

The color interpolation scheme can play an important role in overcoming the physical limitation of the CCD image sensor and in increasing the resolution of color signals, while most conventional approaches result in blurred edges and false color artifacts. In this paper, we have proposed an improved edge-adaptive color interpolation scheme for a progressive scan CCD image sensor with RGB color filter array The edge indicator function proposed utilizes not only the within-channel correlation but also the cross-channel correlation, and reflects the edge characteristics of an image adaptively. The color components unavailable for at each channel are interpolated along the edge direction, not across the edges, so that aliasing artifacts are supressed. Furthermore, we eliminated false color artifacts resulting from the color image formation model in the edge-adaptive color interpolation scheme by adopting the switching algorithm based on the color edge detection. Simulation results of the proposed algorithm indicate that the improved edge-adaptive color interpolation scheme produces quantitatively better and visually more pleasing results than conventional approaches.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.10
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• pp.5861-5865
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• 2013

We investigated the distribution of HPV genotypes in Uyghur women in Xinjiang region of China, and behavioral factors which could predispose them to HPV infection. In this cross-sectional study, women aged 15-59 years were recruited by cluster sampling method in Yutian region in 2009. Liquid-based cytology samples were analyzed centrally for HPV genotype with a linear array detector. Univariate and multivariate logistic regression analyses were performed to identify behavioral risk factors for HPV infection. A total of 883 Uyghur women were recruited successfully. The prevalence of high-risk HPV and low-risk HPV were 7.25% and 1.58%, respectively; the most common HPVs were HPV16, 51, 31, 39 and 58. We found that age of first sexual intercourse was a strong predictor for HPV infection (odds ratio of 4.01 for ${\leq}15$ years versus ${\geq}25$). Having sexual partners ${\geq}3$ was the second predictor (OR 3.69, 95% CI 2.24-7.16). Cleaning the vagina after sex showed an increased risk of HPV infection (OR 2.72; 95% CI 1.98-5.13); Using the condom showed protective factors for HPV infection (OR 0.36; 95%CI0.12-0.53). HPV16, 51, 31, 39 and 58 were the priority types; the age of first sexual intercourse was identified as a major risk factor for HPV infection. Other notable risks were number of sexual partners and cleaning the vagina after sex. Changing these behavioral risk factors could help to reduce the occurrence of cervical cancer in this population.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.8
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• pp.843-850
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• 2012

To satisfy the operational requirements of surveillance radar and the operational concept of a ship combat system, an active-array-type antenna was designed using solid-state transmitters and receivers. The arrangement of the constituent electronic components of the antenna system, considerably large in size, and therefore, the antenna needs to be housed in a box. The rotational antenna system installed on a ship mast is installed in a sealed housing to protect the interior equipment from environmental conditions. The outer shape of the housing is that the antenna should be capable of rotating normally despite strong winds. Furthermore, in recent times, designs with low radar cross section (RCS) have attracted attention from the viewpoint of improving the stealth of the ship. In this light, four types of models are proposed for the outer shape design of the antenna system, and they are investigated from the viewpoint of low RCS design as well as wind load.

• Proceedings of the KIEE Conference
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• 2002.07c
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• pp.1823-1826
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• 2002

The purpose of this experiment was to develope Triggered Vacuum Switch (TVS) for the high voltage and high current. The TVS has an array of rods of alternate polarity in which a fixed gap spacing is maintained between the rods. The cross section of each rod has trapezoidal shape. It consists of electrode, ceramic chamber, getter and trigger. Currently, triggered vacuum switch (TVS) with seal-off has been designed and fabricated at PAL. An experimentation and trigger devices for TVS were designed for testing characteristics of electricity. For making the prototype of TVS, it is developed of fabrication process and fined of electrode material. The fabrication of the TVS is a lot of process which have manufacturing of part, chemical clean, ceramic brazing and metal welding. The fabricated TVS is tested of leak for vacuum, hold-off voltage and conditioning of trigger system. The TVS has pinch-off after it is removed of gas in the TVS and activated of getter in degassing furnace. The prototype TVS tested about 20 kV, 75 kA, 83 ${\mu}s$ with 100 kJ capacitor bank and inductance 5 ${\mu}H$. This paper describes the results of tests and the characteristics of the switch.

• Composites Research
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• v.33 no.1
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• pp.30-37
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• 2020

Stress distributions dependent on fiber arrangements are studied using the two-dimensional representative volume element (RVE) model for uni-directionally continuous fiber-reinforced composites subjected to transverse tensile loading. It is easily expected that the stresses around the fibers are concentrated mainly due to the stiffness mismatch between the fiber and matrix materials. In this presentation, it is shown that the stresses are not always increased although the distance between two fibers is shortened. The 2D RVE models, originally having a regular hexagonal fiber array, is utilized to study the effect of the fiber locations on the stress distributions. As the central fiber is relocated, the stress distributions around the fiber are obtained through finite element analysis. It is found that the stresses around the fiber are strongly dependent on the fiber distance as well as the angle between the loading direction and the line connecting two fibers.

• Journal of the Korean Operations Research and Management Science Society
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• v.37 no.1
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• pp.61-71
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• 2012

Other-regarding preferences (such as trust, reciprocity and altruism) between companies, between consumers and retailers, and between employers and employees are integral elements in determining economic performance. Social trust which is a core element of social capital, especially, is known to reduce transaction costs, help solve collective action problems, and contribute to economic, social, and political development. Therefore, social trust has been given a great deal of attention across an array of academic disciplines for its role in promoting cooperation among individuals and groups, and for its positive influence on economic performance. Most studies describe Korea as a low-trust society than Japan or China. To identify the causes of social trust, this paper focuses on differences of social values (perception on competition and wealth accumulation) in 4 countries (Japan, China, Korea, and United States). Based on World Values Survey data, this paper analyzes effects of the social values on social trust. Social trust was measured by degree to which a respondent thinks that most people can be trusted. Perception on competition was measured by the degree to which a respondent thinks that competition is harmful, and perception on wealth accumulation was done by the degree to which a respondent thinks that wealth can grow so there is enough for everyone. The results showed that social trust was affected by perception on competition and wealth accumulation. A respondent showed higher level of social trust when he (or she) perceived positively competition and wealth accumulation. For enhancing social trust in a country, it is not easy to reduce income inequality and corruption which were reported as causes of social trust by previous studies. Compared to them, social values can be changed more easily by various concrete measures like education and mass-media. Differently from previous studies this paper stresses the concrete measures to enhance social trust in a country.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.49 no.7
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• pp.23-29
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• 2012

The LC-based digitally controlled oscillator (LC-DCO), a key component of the all digital phase locked loop (ADPLL), is designed using $0.18{\mu}m$ RFCMOS process with 1.8 V supply. The NMOS core with double cross-coupled pair is chosen to realize wide tuning range, and the PMOS varactor pair that has small capacitance of a few aF and the capacitive degeneration technique to shrink the capacitive element are adopted to obtain the high frequency resolution. Also, the noise filtering technique is used to improve phase noise performance. Measurement results show the center frequency of 2.7 GHz, the tuning range of 2.5 GHz and the high frequency resolution of 2.9 kHz ~7.1 kHz. Also the fine tuning range and the current consumption of the core could be controlled by using the array of PMOS transistors using current biasing. The current consumption is between 17 mA and 26 mA at 1.8V supply voltage. The proposed DCO could be used widely in various communication system.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.6
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• pp.501-504
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• 2017

In this paper, a hybrid beamforming antenna system using broadband butler matrix and phase shifter is proposed. In the previous works, an $8{\times}8$ butler matrix is used to overcome a drawback of the $4{\times}4$ butler matrix based switched beamforming which provides only 4 beam patterns. However the $8{\times}8$ butler matrix should be designed on the bi-layered substrate using via holes due to its complex structure. It causes performance degradation. To overcome these problems, the proposed hybrid beamforming antenna system is designed on the single side of the substrate for simple structure. By addition of two phase shifter, it provide various beam patterns. The proposed antenna system provides more than 10 dBi radiation gain in the ${\pm}45^{\circ}$ scanning range by 16 input combinations.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.3
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• pp.299-305
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• 2010

In general, the flexible forming die that has been used in the flexible forming process has the identical punch size; hence, its flexibility is relatively low because the range of allowable curvature radii is limited due to the uniform punch tip radius. Hence, a conceptual design of a sectional flexible die is presented for enhancing the flexibility of the forming process. Two punches of different sizes are used to configure the arbitrary forming surface. For a forming region with a relatively large curvature radius, a large punch array block is used; on the other hand, for the forming regions with small curvature radii, a small punch block is used. The cross-sectional profiles are compared with the target shape for evaluating the effectiveness of the process. Consequently, it is confirmed that the sectional flexible die can be used along with a combination of punch blocks of different sizes for manufacturing objective surfaces of complex shapes.