• Title/Summary/Keyword: Computer Aided Engineering

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Feedback Shift Controller Design of Automatic Transmission for Tractors (트랙터 자동변속기 되먹임 변속 제어기 설계)

  • Jung, Gyu Hong;Jung, Chang Do;Park, Se Ha
    • Journal of Drive and Control
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    • v.13 no.1
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    • pp.1-9
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    • 2016
  • Nowadays automatic transmission equipped vehicles prevail in construction and agricultural equipment due to their convenience in driving and operation. Though domestic vehicle manufacturers install imported electronic controlled transmissions at present, overseas products will be replaced by domestic ones in the near future owing to development efforts over the past 10 years. For passenger cars, there are many kinds of shift control algorithms that enhance the shift quality such as feedback and learning control. However, since shift control technologies for heavy duty vehicles are not highly developed, it is possible to improve the shift quality with an organized control method. A feedback control algorithm for neutral-into-gear shift, which is enabled during the inertia phase for the master clutch slip speed to track the slip speed reference, is proposed based on the power transmission structure of TH100. The performance of the feedback shift control is verified by a vehicle test which is implemented with firmware embedded TCU. As the master clutch engages along the predetermined speed trajectory, it can be concluded that the shift quality can be managed by a shift time control parameter. By extending the proposed feedback algorithm for neutral-into-gear shift to gear change and shuttle shift, it is expected that the quality of the shift can be improved.

Computer-aided drug design of Azadirachta indica compounds against nervous necrosis virus by targeting grouper heat shock cognate protein 70 (GHSC70): quantum mechanics calculations and molecular dynamic simulation approaches

  • Islam, Sk Injamamul;Saloa, Saloa;Mahfuj, Sarower;Islam, Md Jakiul;Jahan Mou, Moslema
    • Genomics & Informatics
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    • v.20 no.3
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    • pp.33.1-33.17
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    • 2022
  • Nervous necrosis virus (NNV) is a deadly infectious disease that affects several fish species. It has been found that the NNV utilizes grouper heat shock cognate protein 70 (GHSC70) to enter the host cell. Thus, blocking the virus entry by targeting the responsible protein can protect the fishes from disease. The main objective of the study was to evaluate the inhibitory potentiality of 70 compounds of Azadirachta indica (Neem plant) which has been reported to show potential antiviral activity against various pathogens, but activity against the NNV has not yet been reported. The binding affinity of 70 compounds was calculated against the GHSC70 with the docking and molecular dynamics (MD) simulation approaches. Both the docking and MD methods predict 4 (PubChem CID: 14492795, 10134, 5280863, and 11119228) inhibitory compounds that bind strongly with the GHSC70 protein with a binding affinity of -9.7, -9.5, -9.1, and -9.0 kcal/mol, respectively. Also, the ADMET (absorption, distribution, metabolism, excretion, and toxicity) properties of the compounds confirmed the drug-likeness properties. As a result of the investigation, it may be inferred that Neem plant compounds may act as significant inhibitors of viral entry into the host cell. More in-vitro testing is needed to establish their effectiveness.

[Retracted]Anti-inflammatory activities of octapeptides derived from tertomotide ([논문철회]Tertomotide 유래 옥타펩타이드의 항염증 활성)

  • Lee, Hyosung
    • Journal of Digital Convergence
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    • v.20 no.2
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    • pp.311-316
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    • 2022
  • Tertomotide is a peptide fragment of hTert and developed as a vaccine targeting cancer. It has been reportedly known to ameliorate inflammatory symptoms in clinical tests and in animal studies. However, the therapeutic potential of tertomotide is not supposed to be comparable to conventional anti-inflammatory agents due to low druglikeness In order to treat inflammations present in varous lesion, the structure of tertomotide is required to be modified. In this context, 12 octapeptides were designed based on tertomotide and screened for the anti-inflammatory activity in activated monocyte by measuring TNF-α secretion. As a result, some octapeptides has been exerted anti-inflammatory activity, comparable to or better than tertomotide and estradiol, known anti-inflammatory agents. This result is supposed to be helpful for developing therapeutic purpose exploiting other tertomotide-derived peptides and would be an example for designing novel drug based on active biomolecules with undesirable structure by convergence study of biology and computer-aided medicinal chemistry.

The implementation of cable path and overfill visualization based on cable occupancy rate in the Shipbuilding CAD (조선 CAD에서 선박의 Cable 점유율을 기반으로 Cable 경로 및 Overfill 가시화 구현)

  • Kim, Hyeon-Jae;Kim, Bong-Gi
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.17 no.11
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    • pp.740-745
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    • 2016
  • Cables are installed for tens of thousands of connections between various pieces of equipment to operate and control a commercial ship. The correct shortest-route data is necessary since these are complicated cable installations. Therefore, an overfill interval commonly exists in the shortest paths for cables as estimated by Dijkstra's algorithm, even if this algorithm is generally used. It is difficult for an electrical engineer to find the overfill interval in 3D cable models because the occupancy rate data exist in a data sheet unlinked to three-dimensional (3D) computer-aided design (CAD). The purpose of this study is to suggest a visualization method that displays the cable path and overfill interval in 3D CAD. This method also provides various color visualizations for different overfill ranges to easily determine the overfill interval. This method can reduce cable-installation man-hours from 7,000 to 5,600 thanks to a decreased re-installation rate, because the cable length calculation's accuracy is raised through fast and accurate reviews based on 3D cable visualization. As a result, material costs can also be reduced.

Design of Carrier Recovery Circuit for High-Order QAM - Part I : Design and Analysis of Phase Detector with Large Frequency Acquisition Range (High-Order QAM에 적합한 반송파 동기회로 설계 - I부. 넓은 주파수 포착범위를 가지는 위상검출기 설계 및 분석)

  • Kim, Ki-Yun;Cho, Byung-Hak;Choi, Hyung-Jin
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.38 no.4
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    • pp.11-17
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    • 2001
  • In this paper, we propose a polarity decision carrier recovery algorithm for high order QAM(Quadrature Amplitude Modulation), which has robust and large frequency acquisition performance in the high order QAM modem. The proposed polarity decision PD(Phase Detector) output and its variance characteristic are mathematically derived and the simulation results are compared with conventional DD(Decision-Directed) method. While the conventional DD algorithm has linear range of $3.5^{\circ}{\sim}3.5^{\circ}$, the proposed polarity decision PD algorithm has linear range as large as $-36^{\circ}{\sim}36^{\circ}$ at ${\gamma}-17.9$. The conventional DD algorithm can only acquire offsets less than ${\pm}10\;KHz$ in the case of the 256 QAM while an analog front-end circuit generally can reduce the carrier-frequency offset down to only ${\pm}100\;KHz$. Thus, in this case additional AFC or phase detection circuit for carrier recovery is required. But by adopting the proposed polarity decision algorithm, we can find the system can acquire up to ${\pm}300\;KHz$at SNR = 30dB without aided circuit.

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A Study on the Thermo-Mechanical Stress of MEMS Device Packages (마이크로 머신(MEMS) 소자 패키지의 열응력에 대한 연구)

  • Jeon, U-Seok;Baek, Gyeong-Uk
    • Korean Journal of Materials Research
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    • v.8 no.8
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    • pp.744-750
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    • 1998
  • Unlike common device, MEMS(micro-electro-mechanical system) device consists of very small mechanical structures which determine the performance of the device. Because of its small mechanical structure inside. MEMS device is very sensitive to thermal stress caused by CTE(coefficient of thermal expansion) mismatch between its components. Therefore, its characteristics are affected by material properties. process temperature. and dimensions of each layer such as chip, adhesive and substrate. In this study. we investigated the change of the thermal stress in the chip attached to a substrate. With computer-aided finite element method (FEM), the computer simulation of the thermal stress was conducted on variables such as bonding material, process temperature, bonding layer thickness and die size. The commercial simulation program, ABAQUS ver5.6, was used. Subsequently 3-layer test samples were fabricated, and their degree of bending were measured by 3-D coordinate measuring machine. The experimental results were in good agreement with the simulation results. This study shows that the bonding layer could be the source of stress or act as the buffer layer for stress according to its elastic modulus and CTE. Solder adhesive layer was the source of stress due to its high elastic modulus, therefore high compressive stress was developed in the chip. And the maximum tensile stress was developed in the adhesive layer. On the other hand, polymer adhesive layer with low elastic modulus acted as buffer layer, and resulted in lower compressive stress. The maximum tensile stress was developed in the substrate.

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Development of a Simulation Prediction System Using Statistical Machine Learning Techniques (통계적 기계학습 기술을 이용한 시뮬레이션 결과 예측 시스템 개발)

  • Lee, Ki Yong;Shin, YoonJae;Choe, YeonJeong;Kim, SeonJeong;Suh, Young-Kyoon;Sa, Jeong Hwan;Lee, JongSuk Luth;Cho, Kum Won
    • KIPS Transactions on Software and Data Engineering
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    • v.5 no.11
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    • pp.593-606
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    • 2016
  • Computer simulation is widely used in a variety of computational science and engineering fields, including computational fluid dynamics, nano physics, computational chemistry, structural dynamics, and computer-aided optimal design, to simulate the behavior of a system. As the demand for the accuracy and complexity of the simulation grows, however, the cost of executing the simulation is rapidly increasing. It, therefore, is very important to lower the total execution time of the simulation especially when that simulation makes a huge number of repetitions with varying values of input parameters. In this paper we develop a simulation service system that provides the ability to predict the result of the requested simulation without actual execution for that simulation: by recording and then returning previously obtained or predicted results of that simulation. To achieve the goal of avoiding repetitive simulation, the system provides two main functionalities: (1) storing simulation-result records into database and (2) predicting from the database the result of a requested simulation using statistical machine learning techniques. In our experiments we evaluate the prediction performance of the system using real airfoil simulation result data. Our system on average showed a very low error rate at a minimum of 0.9% for a certain output variable. Using the system any user can receive the predicted outcome of her simulation promptly without actually running it, which would otherwise impose a heavy burden on computing and storage resources.

Comparative Analysis of Effective RCS Prediction Methods for Chaff Clouds (효과적인 채프 구름의 RCS 예측 방법 비교 분석 연구)

  • Kim, Min;Lee, Myung-Jun;Lee, Seong-Hyeon;Park, Sung-ho;Kong, Young-Joo;Woo, Seon-Keol;Kim, Hong-Rak;Kim, Kyung-Tae
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.29 no.3
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    • pp.233-240
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    • 2018
  • Radar cross section (RCS) analysis of chaff clouds is essential for the accurate detection and tracking of missile targets using radar. For this purpose, we compare the performance of two existing methods of predicting RCS of chaff clouds. One method involves summing up the RCS values of individual chaffs in a cloud, while the other method predicts the RCS values using aerodynamic models based on the probability density function. In order to compare and analyze the two techniques more precisely, the RCS of a single chaff computer-aided design model consisting of a half wavelength dipole was calculated using the commercial electromagnetic numerical analysis software, FEKO 7.0, to estimate the RCS values of chaff clouds via simulation. Thus, we verified that our method using the probability density distribution model is capable of analyzing the RCS of chaff clouds more efficiently.

Influence of Design Variables on Flow Characteristics of Poppet Valve using Analysis of Means (평균분석을 이용한 설계변수가 포핏 밸브의 유동특성에 미치는 영향)

  • Jeong, Ja-Young;Choi, Eun-Ho;Kang, Young-Jin;Noh, Yoojeong;Lim, O-Kaung
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.30 no.3
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    • pp.239-248
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    • 2017
  • According to the structure, solenoid valve can be categorized as spool valve or poppet valve. While various research on spool valve which has simple structure and fine susceptibility to contamination has been conducted, poppet valve which has less susceptibility to contamination and advantage in a long time operation still need much research because of its complicated structure. In order to design the poppet valve, various parameters such as the diameter of the poppet, the angle of the poppet, the diameter of the disk, the spring stiffness, the spring preload and flow path structure should be considered. Conventional studies on poppet valve usually take only one design parameters and did not much focused on the effect of the parameters on flow characteristics. In this paper, the change of the flow characteristics according to the design parameters of the poppet valve for 3/2Way solenoid valve is analyzed. The previous studies and the results of initial model analysis was referred for the selection of the design parameters. The effects of design parameters on maximum pressure, minimum pressure, and pressure drop was examined using analysis of means(ANOM).

Design Optimization of Two-Way Pump Casing through Flow Analysis (양방향 펌프의 유동 해석을 통한 펌프 케이싱의 최적설계)

  • Kim, Dong-Hwi;Noh, Yoojeong;Lim, O-Kaung;Choi, Eun-Ho;Choi, Ju Yong
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.31 no.2
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    • pp.79-85
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    • 2018
  • A two-way pump can reduce costs by draining and circulating water out and into the drum of the washing machine using a single motor whereas a conventional one-way pump uses two motors for doing the same function. However, when the water is drained through the drainage outlet in the two-way pump casing, a backward or inhalation flow occurs and the water flows to the circulation outlet. Likewise, when the water is circulated, the backward flow or inhalation makes the water flow to the drainage outlet. In this study, design optimization of the two-way pump casing is performed to maximize its performance while improving backward flow and inhalation occurring inside of the pump casing. For this, design variables of the pump casing that mainly affect the performance of the pump such as flow rate and torque of the motor were selected through the analysis of mean. Using response surface models for the performances, the ratio of the flow rate to the torque was maximized with satisfying the constraints for the back flow and inhalation through design optimization.