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강진규 ( Jingyu Kang ),김관수 ( Kwansoo Kim ) 한국농업경제학회 2020 農業經濟硏究 Vol.61 No.4
Since 2014, fine dust particles have emerged as one of major social issues in South Korea. The density of fine dust has been announced in the weather forecast since then, and the number of related media reports has rapidly increased. As the hazard of fine dust has been recognized, comfort food consumption has begun in order to reduce anxiety. Pork belly is a typical comfort food due to the myth that the fat in it helps release fine dust. The research question is how consumption behavior changes, as the fine dust problem is taken seriously under condition that a groundless belief, that pork belly is effective in getting fine dust out of the body, is widespread. It is assumed that the more seriously the problem is taken, the more pork belly consumption occurs. The Almost Ideal Demand System (AIDS) is used to test the hypothesis. The relationship between pork belly consumption and the density of fine dust was previously analyzed. This study additionally finds the effect of the number of media reports regarding fine dust particles. Note that fine dust has been recognized as a serious problem since 2014, when related reports have remarkably increased. Using the AIDS model, we examined how the expenditure share of pork belly, pork excluding pork belly, beef, chicken, or other meat depends on explanatory variables such as the price of each item, the density of fine dust, and the proportion of news reports. We found that, when the ratio of related reports increases, the expenditure share of pork belly grows. An elasticity analysis shows that consumption of pork belly increases, as fine dust-related reports ratio is higher. When the ratio increases by 10%, consumption of pork belly increases by 0.33%. This phenomenon is based on the myth, which people believe in that pork belly is effective in getting fine dust out of the body. The problem is that belief lacks scientific evidence. If consumption of pork belly increases because of inaccurate information, consumers may fail to achieve maximum utility.
Hybrid RCD-WTA Multiplexer for MR-compatible PET Detector
Jingyu Yang,Minho Lee,Jihoon Kang 한국자기학회 2020 Journal of Magnetics Vol.25 No.4
A hybrid multiplexer readout circuit one dimensional resistive charge division (1D-RCD) chain and winner takes all (WTA) circuit was proposed for MR-compatible PET detector modules. To prove the effectiveness of the circuit, three different readout circuits including WTA, 2D-RCD and proposed hybrid RCD-WTA multiplexer were evaluated for 4 × 4 LYSO-GAPD PET detector. Various parameters were precisely measured and quantitatively characterized. While there were considerable differences observed in rise time, fall time, pulse width and amplitude of analog output waveforms for each circuit, the detector performance was quite similar in crystal identification and energy resolution. However, pincushion distortion was observed in the flood histogram of 2D-RCD, and spatial linearity was relatively degraded. The coincidence time resolutions were 487 ps, 955 ps, and 676 ps for WTA, 2D-RCD, and hybrid RCD-WTA multiplexer, respectively. These results demonstrated that proposed hybrid multiplexer could effectively reduce the number of analog electronic channels from N² to only 2 for an N × N photosensor array, while maintaining intrinsic performance of multichannel PET detector requiring energy, position and time information for incidence photons.
Research Progress of the Structure Vibration-Attitude Coordinated Control of Spacecraft
Jingyu Yang,Shiying Qu,Jiahui Lin,Zhiqi Liu,Xuanming Cui,Chu Wang,Dujiang Zhang,Mingcheng gu,Zhongrui Sun,Kang Yang,Lanwei Zhou,Guoping Chen 한국항공우주학회 2015 International Journal of Aeronautical and Space Sc Vol.16 No.4
This paper gives an overview of research on the field of structure vibration-attitude coordinated control of spacecraft. First of all, the importance of the technology has been given an introduction, and then later the research progress of space structure dynamics modeling, research progress of structure vibration-attitude coordinated control of flexible spacecraft have been discussed respectively. Finally, future research on application of structure vibration-attitude coordinated control of spacecraft has been recommended.
Kang Liu,Guoming Chen,Gaogeng Zhu,JINGYU ZHUANG 대한조선학회 2019 International Journal of Naval Architecture and Oc Vol.11 No.1
Marine production strings are continuously affected by unstable internal fluid during operation. In this paper, the structural governing equation for marine production string self-induced vibration is constructed. A finite element analysis model is established based on Euler-Bernoulli theory and solved by the Newmark method. Furthermore, based on reliability theory, a self-design procedure is developed to determine the operability envelope for marine production string self-induced vibration. Case studies show: the response frequency of the production strings is consistent with the excitation frequency under harmonic fluctuation and mainly determined by the first-order natural frequency under stochastic fluctuation. The operability envelope for marine production string self-induced vibration is a near symmetrical trapezium. With the increasing of natural gas output, the permissible fluctuation coefficient dramatically decreases. A reasonable centralizer spacing, increasing top tension, and controlling natural gas output are of great significance to the risk control in marine production string operation.
Scalability evaluation of resistor charge division circuit for PET detector based on GAPD
Jingyu Yang,Hea Ryeong Lee,Jihoon Kang 한국자기학회 2021 한국자기학회 학술연구발표회 논문개요집 Vol.31 No.1
Performance evaluation was characterized the scalability of resister charge division (RCD) circuit for positron emission tomography (PET) detector based on Geiger-mode avalanche photodiode (GAPD). PET detectors with different scales (4 × 4, 4 × 8, and 4 × 12 array) were consists of LYSO - GAPD array with a pixel pitch of 3.36 mm. All of signals from GAPD array were multiplexed by the RCD circuits to reduce the number of output channels from N × M to 4 for N by M array. Experimental measurements were performed by using a Na-22 point source placed 100 mm away from the top surface of the PET detector module for uniformly irradiation. The following four parameters were measured for analog output signals of different PET detectors: Amplitude, rise time, fall time, and pulse width. In addition, the following three investigations were performed for characterization of PET detector performance: Flood histogram, energy spectra and count rate. Experimental results show that rise time, fall time, and pulse width of waveforms were increased larger than 3-times as increasing scale of detector arrays. Although the considerable degradations were observed in spatial linearity including pincushion distortion (Fig. 1), the detector performances including position determination, energy resolution (~10.5%) and dead time loss were quite similar for the three types of PET detector module. This results revealed that RCD circuit could provide the extendibility for 4 × 12 array PET detector module with the moderate analog signal degradations and comparable PET detector performances.