이중 에너지 CT 영상에서 피팅 함수에 따른 물질 분해 알고리즘 성능 비교

Hojin Jung,Chulhee Han,Jongduk Baek 대한전자공학회 2019 대한전자공학회 학술대회 Vol.2019 No.6

Dual-energy based CT technique separates the each component of CT image by the material decomposition algorithm. The material decomposition algorithm enables to increase the contrast of CT imags by combining the resultant materials, however, the performance depends on the fitting functions. In this work, we compare the performance of the material decomposition algorithms with various fitting functions (Polynomial fitting, delaunay triangulation based linear, cubic spline, and biharmonical spline interpolation) and propose the optimal fitting function using mean-squared error (MSE). The results show that cubic spline function based material decomposition algorithm shows the best performance in material separation with reasonable processing time.

Serotonergic Signaling in Adipocytes is Critical for Insulin Triggering Adipogenesis

Hojin Lee,Soomin Lee,Jung-Mi Oh,Seoyeong Jung,Hye-Young Joung,Sun Young Park,Sungkun Chun,Jaekwang Lee 한국식품영양과학회 2021 한국식품영양과학회 학술대회발표집 Vol.2021 No.10

5-Hydroxytryptamine (5-HT, serotonin), a monoamine neurotransmitter derived from the amino acid tryptophan, is related to body weight and food intake regulation. Although serotonin signaling is important to develop obesity in the central nervous system, however, it is unclear what the role of serotonin signaling to develop adiposity in peripheral system. In this study, we showed that serotonin was synthesized in adipocytes, regulated adipogenesis by increase of ROS which was produced during serotonin metabolism by monoamine oxidases (MAOs) in adipocyte differentiation. Interestingly, we found that among MAOs, MAO-B was upregulated during differentiation in 3T3L1 and primary adipocytes. In the same line, increased ROS production during adipogenesis was blocked by selegiline, MAO-B inhibitor, in 3T3L1 and primary adipocyte. Moreover, the high-fat diet (HFD) fed mice with the administration of selegiline showed weight loss and reduction of fat size. Consequently, these data suggest that adipocyte is serotonergic cell and adipocytes synthesize serotonin and produce ROS during serotonin degradation by MAO enzymes, specially MAO-B, which could be a therapeutic target for anti-obesity.

A Conceptual Model of a B2B Food Distribution Platform Based on Blockchain Consensus Mechanism

Hojin Jung 한국콘텐츠학회(IJOC) 2021 International Journal of Contents Vol.17 No.3

We proposed a B2B food distribution platform by transforming an established food distribution and management platform based on blockchain technology. Our proposed model introduced a method to bring innovation into the domestic B2B food distribution market and systematically manage and utilize massive data (country of origin, producer, transaction, distributor, final consumer) generated within the food distribution process.

Design, Analysis, and Equivalent Circuit Modeling of Dual Band PIFA Using a Stub for Performance Enhancement

Hojin Jung,Kwangho Kim,Wansoo Nah,Jawad Yousaf 한국전자파학회JEES 2016 Journal of Electromagnetic Engineering and Science Vol.16 No.3

This work presents a new method for enhancing the performance of a dual band Planer Inverted-F Antenna (PIFA) and its lumped equivalent circuit formulation. The performance of a PIFA in terms of return loss, bandwidth, gain, and efficiency is improved with the addition of the proposed open stub in the radiating element of the PIFA without disturbing the operating resonance frequencies of the antenna. In specific cases, various simulated and fabricated PIFA models illustrate that the return loss, bandwidth, gain, and efficiency values of antennas with longer optimum open stub lengths can be enhanced up to 4.6 dB, 17%, 1.8 dBi, and 12.4% respectively, when compared with models that do not have open stubs. The proposed open stub is small and does not interfere with the surrounding active modules; therefore, this method is extremely attractive from a practical implementation point of view. The second presented work is a simple procedure for the development of a lumped equivalent circuit model of a dual band PIFA using the rational approximation of its frequency domain response. In this method, the PIFA’s measured frequency response is approximated to a rational function using a vector fitting technique and then electrical circuit parameters are extracted from it. The measured results show good agreement with the electrical circuit results. A correlation study between circuit elements and physical open stub lengths in various antenna models is also discussed in detail; this information could be useful for the enhancement of the performance of a PIFA as well as for its systematic design. The computed radiated power obtained using the electrical model is in agreement with the radiated power results obtained through the full wave electromagnetic simulations of the antenna models. The presented approach offers the advantage of saving computation time for full wave EM simulations. In addition, the electrical circuit depicting almost perfect characteristics for return loss and radiated power can be shared with antenna users without sharing the actual antenna structure in cases involving confidentiality limitations.

Real-Time Individual Tire Force Estimation for an All-Wheel Drive Vehicle

Jung, Hojin,Choi, Seibum B. IEEE 2018 IEEE Transactions on Vehicular Technology VT Vol.67 No.4

<P>Due to demands for active control systems that can enhance driving performance, active-type all-wheel drive (AWD) systems have drawn interest recently. Equipped with an electronically actuated motor to control a wet clutch in a transfer case, the active-type AWD facilitates the variable distribution of torque from the main driveshaft to the subdriveshaft. The conventional approaches to the estimation of tire force, developed to implement chassis control, have only focused on the two-wheel drive vehicle dynamics model. In this paper, an individual tire force estimation algorithm that is particularly designed for AWD vehicles is proposed. Using the interacting multiple model filter method, the suggested algorithm can help avoid the chattering response caused by immediately switching between vehicle dynamic models. Data obtained from the controller area network of production vehicles were used for the real-time application of the proposed estimator to chassis control. Then, the proposed estimator was validated using an AWD vehicle in various driving scenarios.</P>

Does a Lingua Franca Matter in Bilateral International Trade?

Hojin Jung(정호진),Li Su,Mingzhuo Yang 한국산업경제학회 2020 한국산업경제학회 정기학술발표대회 논문집 Vol.2020 No.12

MODEL PREDICTIVE CONTROL OF AN ALL-WHEEL DRIVE VEHICLE CONSIDERING INPUT AND STATE CONSTRAINTS

Hojin Jung,Beomjoon Pyun,Seibum Choi 한국자동차공학회 2020 International journal of automotive technology Vol.21 No.2

This paper suggests a novel model-based control scheme for an all-wheel drive (AWD) vehicle. Using transfer case, AWD system is able to transfer the engine torque to all the wheels mechanically, helping the vehicle to maintain traction on a slippery road or to climb a hill. Recently, an active type AWD system that is able to control the torque transmitted through transfer case continuously by the aid of electronic clutch actuator has become popular. In order to realize preemptive operation which is necessary property for AWD system while simultaneously considering states and input constraints which is originated from mechanical and physical characteristics, this paper adopted model predictive control (MPC) concept. The proposed MPC-based controller was designed by using planar full-car model that is based on tire force and motion states, which represents the direct relationship between these states and control input. Therefore, the planar full-car model contributed the suggested controller to follow standard MPC design process. The target states of longitudinal wheel slip and yaw rate, which have commonly been adopted in previous studies, were selected for practical concerns. The advantages of the suggested MPCbased controller that is designed especially for an AWD system were validated by conducting simulations through a Simulink- CarSim-based AWD vehicle model.

효율적인 복합재난 대응을 위한 복합시나리오 개발 방안 (방사능 사고 + 화학사고 복합유형을 중심으로 : 울산지역)

정호진(Hojin Jung),은종화(Chonghwa Eun),문일(Il Moon) 한국위험물학회 2021 한국위험물학회지 Vol.9 No.2

This study aims to develop the multi-scenario plan for the efficient response to ‘complex-disaster.’ Looking at the disaster situations that occur in our society, it shows a complex aspect in which several types of disasters occur simultaneously as subsequent disasters are induced from the underlying disasters that have a leading influence. Although it is necessary to prepare meticulously prepared countermeasures according to various disaster situations, the current understanding of ‘complex-disaster’ situation, as well as response plans for each type of disaster, is insufficient. In this context, this paper proposes a development theory for developing scenarios to for response to complex ‘complex-disasters’ based on chemical accident with radioactive disaster.

정보화 시대의 불평등과 성장: 중국 사례에 근거하여

정호진 ( Hojin Jung ),최창규 ( Changkyu Choi ),( Li Su ) 서강대학교 지암남덕우경제연구원(구 서강대학교 시장경제연구소) 2021 시장경제연구 Vol.50 No.2

중국의 성별 패널데이터를 이용하여 본 연구는 불평등과 인터넷 사용 수준이 중국의 경제 성장에 어느 정도 영향을 미치는지 실증분석 하였다. 불평등과 정보기술이 경제성장에 긍정적인 영향을 미친다는 본 연구의 실증분석 결과는, 이 두 변수가 지역별 성장 격차를 설명하는데 중요한 역할을 한다는 것을 의미한다. 특히 우리는 실증분석 결과가 다양한 회귀식 모형에서뿐만 아니라 내생성 문제를 통제한 후에도 강건함을 보여 주었다. 본 연구는 인터넷 접근성을 높이고 경제성장을 지연시키지 않도록 점진적인 재분배정책을 고려할 필요가 있다는 점을 시사한다. We use province-level panel data to determine the extent to which inequality and internet usage affect economic growth in China. We found that both variables-inequality and information technology-positively impact growth, indicating that these factors play critical roles in explaining the growth gap. This finding was robust to various specifications even after controlling for possible endogeneity issues. Our result suggests that policymakers would do well to eliminate barriers to Internet access and consider policies that encourage gradual redistribution of income in order to maintain economic growth.

실험계획법을 이용한 자동차 시트 구조물 최적설계 및 해석 연구

정호진(Hojin Jung),이대섭(Daesuep Lee),권영두(Youngdoo Kwon),한덕희(Duckhe Han) 한국자동차공학회 2010 한국자동차공학회 학술대회 및 전시회 Vol.2010 No.11

In modern times, development trend of automobiles is the tendency to prefer the high fuel efficiency of automobile. Also, the structure of seat that takes 4% of automobile’s weight is the target to be secured the stability enough and attain the lightweight, To meet this, the characteristics of load to be applied to seat structure must be analyzed from the initial time, and it must be considered and designed material, thickness, distance to be assembled with recliner and condition of section through the calculation of numerical value. This study performed to reduce stress and moments to be occurred to seat frame through keep the optimum condition with D.O.E for cushion frame of seat due to passenger inertia weight at the rear Collision of automobile, This study looked for optimum values with Minitap and analyzed the cushion frame of seat with LS-DYNA, FEA tool, according to those Factor