• Bulletin of the Korean Chemical Society
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• v.30 no.11
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• pp.2749-2753
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• 2009

Structural characteristics that influence on the insecticidal activity ($pI_{50}$) of 2-(n-octyl)isothiourea analogues (1-45) against the diamondback moth (Plutella xylostella, L.) based on three dimensional quantitative structure activity relationships (3D-QSARs) were discussed quantitatively using a comparative molecular field analysis (CoMFA) and a comparative molecular similarity indeces analysis (CoMSIA) methods. The statistical values of the CoMFA 2 model were better than those of the CoMSIA 1 model. The CoMFA 2 model was the optimized model with the correlativity (the training set: Ave. = 0.104 & PRESS = 0.613) and the predictability (the test set: Ave. = 0.086 & PRESS = 0.096). Insecticidal activities with the optimized CoMFA 2 model were dependent upon steric factors (79.4%) of $R_1-R_3$ substituents. From the analytical results of CoMFA contour maps, it is predicted that the R1 substituent of 1-45 which has a steric favor in a broad space, $R_2\;and\;R_3$ groups with a steric favor in a narrow space and a H-bond donor favor would have better the insecticidal activity.

• Journal of Magnetics
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• v.22 no.1
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• pp.69-77
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• 2017

To empower safe, economical and eco-friendly sustainable solution for enhancing oil and gas productivity from deep water reservoirs, new downhole technologies are recommended. Since electric machine plays leading role in the downhole application, it is a squeezing requirement for researchers to design and develop advanced electric machine. The Recent improvement in technology and uses of high-temperature magnets, permanent magnet flux switching machine (PMFSM) has become one of the appropriate contenders for offshore drilling but fewer designed for downhole due to ambient temperature. Therefore this comprehensive study deals with the design optimization and performance analysis of outer rotor PMFSM for the downhole application. Preliminary, the basic design parameters needed for machine design are calculated mathematically. Then the design refinement technique is implemented through deterministic method. Finally, initial and optimized performance of the machine is compared and as a result the output torque is increase from 16.39 Nm to 33.57 Nm while diminishing the cogging torque and PM weight up to 1.77 Nm and 0.79 kg, respectively. Therefore, it is concluded that purposed optimized design is suitable for the downhole application.

• The Transactions of the Korean Institute of Power Electronics
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• v.25 no.1
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• pp.21-28
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• 2020

Integrated bidirectional OBC/LDC was developed to reduce the volume for elements, avoid space restriction, and increase efficiency in EV vehicles. In this study, a DC-DC converter in integrated OBC/LDC circuits was composed of an SRC circuit with a stable output voltage relative to an LLC circuit using a theoretical method and simulation. The resonant network of the selected circuit was optimized to minimize the power loss and element volume under constraints for the buck converter and the battery charging range. Moreover, the validity of the optimal model was verified through an analysis using a theoretical method and a numerical analysis based on power loss at the optimized resonant frequency.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.23 no.7
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• pp.669-674
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• 2013

To design the optimized low noise planetary gear sets, a program called pRMC(planetary run many cases) is developed. The pRMC is especially using a combination analysis method for all gear specifications and also able to analyze any type of planetary gear sets. The pRMC is composed of the 5 sections those are generate, setting, evaluate, combine and analysis. After calculating all candidate gear sets, the pRMC could show many results that represent the character of each gear set including the transmission error which is the main gear noise factor, the contact ratios, the bending stress and so on. By comparing the results objectively, user could predict and select the optimized gear set which has quiet noise level and desired durability. The planetary gear designed by pRMC could have reduced noise and vibration level from 5 to 10 dB than previous-designed one.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.1051-1054
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• 2005

On this study, we optimized minimizing the characteristic function for mixed result of the structural contact analysis and the buckling analysis according to the pin jig initial model's level change using mixed the table of orthogonal away and ANOM, Pin jig's weight is reduced up to 20 percent considering constraint conditions. Also we optimized reducing 20 percent weight of pin jig model using topology optimization.

• Journal of Microbiology and Biotechnology
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• v.29 no.4
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• pp.617-624
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• 2019

Bacterial nanocellulose (BNC) which is generally synthesized by several species of bacteria has a wide variety of industrial uses, particularly in the food and material industries. However, the low levels of BNC production during the fermentation process should be overcome to reduce its production cost. Therefore, in this study, we screened and identified a new cellulose-producing bacterium, optimized production of the cellulose, and investigated the morphological properties of the cellulosic materials. Out of 147 bacterial isolates from ripened fruits and traditional vinegars, strain SFCB22-18 showed the highest capacity for BNC production and was identified as Komagataeibacter sp. based on 16S rRNA sequence analysis. During 6-week fermentation of the strain using an optimized medium containing 3.0% glucose, 2.5% yeast extract, 0.24% acetic acid, 0.27% $Na_2HPO_4$, and 0.5% ethanol at $30^{\circ}C$, about 5 g/l of cellulosic material was produced. Both imaging and IR analysis proved that the produced cellulose would be nanoscale bacterial cellulose.

• Journal of Information Processing Systems
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• v.18 no.3
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• pp.374-388
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• 2022

Database systems usually have many parameters that must be configured by database administrators and users. RocksDB achieves fast data writing performance using a log-structured merged tree. This database has many parameters associated with write and space amplifications. Write amplification degrades the database performance, and space amplification leads to an increased storage space owing to the storage of unwanted data. Previously, it was proven that significant performance improvements can be achieved by tuning the database parameters. However, tuning the multiple parameters of a database is a laborious task owing to the large number of potential configuration combinations. To address this problem, we selected the important parameters that affect the performance of RocksDB using random forest. We then analyzed the effects of the selected parameters on write and space amplifications using analysis of variance. We used a genetic algorithm to obtain optimized values of the major parameters. The experimental results indicate an insignificant reduction (-5.64%) in the execution time when using these optimized values; however, write amplification, space amplification, and data processing rates improved considerably by 20.65%, 54.50%, and 89.68%, respectively, as compared to the performance when using the default settings.

• Nuclear Engineering and Technology
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• v.53 no.1
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• pp.344-350
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• 2021

As the High Flux Advanced Neutron Application Reactor (HANARO) has been recently required to support new R&D relevant to future nuclear systems requiring a much higher neutron fluence, the development of irradiation capsule technology for long-term irradiation testing was performed in three steps (3, 5, 10 dpa). At first, several design improvements of a standard capsule were suggested based on a failure analysis of the capsule and successfully applied for irradiation testing at HANARO at up to eight reactor operation cycles equivalent to 3 dpa. Based on a schematic stress analysis of the vulnerable parts of the previous capsule, an optimized design of the capsule was made for 5 dpa irradiation. The newly designed capsule was safely out-pile tested up to 450 days, which was equivalent to 5 dpa irradiation in the reactor. The test results were submitted to the Reactor Safety Review Committee of HANARO and irradiation testing for 5 dpa was approved. The capsule was also successfully out-pile tested to evaluate the possibility of irradiation testing for 10 dpa. For a higher neutron fluence exceeding 10 dpa, new capsule technologies, including a new capsule that has a different bottom design and neutron flux boosting capsule, were also suggested.

• Progress in Superconductivity and Cryogenics
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• v.12 no.2
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• pp.17-20
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• 2010

A considerable amount of research material discussing designs and properties of High Temperature Superconducting Fault Current Limiter (HTS FCL) is available. However, a shortage of research concerning positioning of HTS FCL in power grid is felt. In this paper a feasibility study of HTS FCL positioning in Smart Grid through simulation analysis is carried out. A complete power network (including generation, transmission and distribution) is modeled in Simulink / SimPowerSystems. A generalized HTS FCL is also designed by integrating Simulink and SimPowerSystem blocks. The distribution network of the model has a wind turbine attached to it forming a micro grid. Three phase fault have been simulated along with placing FCL models at key points of the distribution grid. It is observed that distribution grid, having distributed generation sources attached to it, must not have a single FCL located at the substation level. Optimized HTS FCL location regarding the best fault current contribution from wind turbine has been determined through simulation analysis.

• The Journal of the Acoustical Society of Korea
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• v.27 no.6
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• pp.263-270
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• 2008

The performance of an ultrasonic array sensor is determined by the properties of constituent materials and the effects of many structural parameters. In this study, with the finite element method, variation of the performances of an ultrasonic array sensor was analyzed in relation to its structural variables. Based on the analysis result, the structure of the ultrasonic array sensor was optimized to provide the highest sensitivity while satisfying such requirements as fractional bandwidth, center frequency and -20 dB pulse length. The optimization was carried out with the SQP-PD method for a target function composed of the ultrasonic array sensor performance. The optimized ultrasonic array sensor satisfied all the required specifications to be applicable to medical imaging diagnosis. The design technology in this paper can be utilized for other ultrasonic array sensors of a similar structure.