• Proceedings of the KSR Conference
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• 2008.11b
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• pp.219-224
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• 2008

The purpose of this paper is to acquire the data related to insulation evaluation of hybrid vehicle traction motors. We carried out a comparative analysis on Insulation Resistance (IR) and Polarization Index (PI) of motor stators according to IEEE Std. 43 and IEC 60085-1 for insulation resistance test standard of rotating machinery. Maximum test voltage which is applied to between a phase and enclosure was set at 500 V. The IRs of the used motors were lower than those of the new ones. The PIs of the used motor were ranges from 0.74 to 1.1 and did not meet the recommendation basis 2 for insulation level H. From the experimental results, we could prepare parameters and basis for insulation evaluation of motor stators by comparative analysis of the IR and the PI.

• 제어로봇시스템학회:학술대회논문집
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• 1988.10a
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• pp.137-141
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• 1988

A sampled data controller for the quadruped walking robot is presented. To provide systematic design procedure, the relation between PI gain of velocity controller and sampling rate is analyzed with the ISE performance index and the time responses. The position controller for one-leg, 3-axis, was developed under consideration of compactness and expendability. And several experiments were performed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.16 no.6
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• pp.509-516
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• 1991

In this paper, we propose on objective evaluation model of telephone transmission qulity in order to estimate a satisfaction score regarding speech quality in a relephone network. As the degradantion factors of telephone transmission quality, this model takes into account transmission loss, noise, distortion, talker echo and sidetone. A performance index[PI] is introduced for five psychological factors affecting telephone speech qualty, and a Mean Opinion Score(MOS) is estimated from the sum of all Pis. The simulation results indicate theat the MOS obtained from the objective evaluation model is in good agreement with that of subjective evaluation.

• Journal of Practical Agriculture & Fisheries Research
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• v.24 no.1
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• pp.29-35
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• 2022

This study was conducted to investigate the seed storage method and seed germination characteristics of Synurus deltoides (Ait.) Nakai, a kind of wild vegetables. Several parameters affecting seed germination, such as germination temperature, chilling duration, imbibition duration, and storage method were evaluated. The seed germination of Synurus deltoides showed the highest germination rate (GR), promptness index (PI), germination performance index (GPI), mean daily germination (MDG) at 25℃. This implies that the optimum germination temperature was 25℃. And also, Seeds stored at -4℃, after 150 days showed relatively high germination rate about 98%. Therefore, The optimum germination temperature of Synurus deltoides was 25℃ and to increase the germination rate over 98% of Synurus deltoides, cold-wet storage 20 days treatments at 4℃ were effective in the improvement of seed germination.

• Advances in materials Research
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• v.13 no.1
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• pp.19-35
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• 2024

Presented Article evaluates the effect of nanoclay on permeability, compressive strength, and plasticity behavior of fine-grained soil related to the Tabriz landfill site. In this regard, comprehensive experimental study was performed on taken soil samples (42 specimens) with aim of design high-performance liners for Tabriz landfill. The samples was mixed by 0% (control) 3%, 6% and 9% nanoclay and prepared in 1, 7, 14 and 28 days before testing stage. Index tests like particle-size, permeability, atterberg limits, and uniaxial compressive strength (UCS) was conducted on samples. The results show that studied soil is classified as CL in USCS classification and atterberg limits measured as LL is 37, PL is 20.67, and PI is 16.33 which increase into 75, 45, and 30. The assessment presented the LL was increased about 20.27% based on increasing in nanoclay from 0% to 9%. These variations for PL and PI were 21.77% and 18.37%, respectively. Also, the and soil's compressive strength is increase from 120 kPa to 188 kPa and permeability is estimated as 4.25×10^-6 m/s which reduced into the 6.34×10^-9 m/s with respect the naboclay content increases form 0% to 9%.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.3
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• pp.503-510
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• 2021

This study intends to apply the mathematical method of fractional order differentiation to a controller that controls the response of the system. Therefore, we design integrator for the fractional index by converting it into discrete time to construct a controller. The IP controller composes an integral controller for errors and the proportional controller applies only the system output. The controller is designed by using the fractional order integrator to the integral controller of the IP controller. First, the performance of the PI controller and the IP controller is compared, and the designed controller is applied to the speed control of the motor. As a result, the motor output speed was uniformed and precise control performance could be obtained. It was confirmed that the speed error in the steady state is within 0.1 [%], and it has precise and uniform speed control performance without overshoot.

• Journal of the Korean Wood Science and Technology
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• v.51 no.4
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• pp.295-308
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• 2023

This study applied a real-time IoT (Internet of Things) environmental monitoring system to wooden cultural heritages (WCHs) located in suburbs and forests in Korea. It automated the graphs of seasonal Temperature (T) and relative humidity (RH) changes inside the heritage structures and seasonal Performance Index (PI) values. While utilizing line graphs of the existing T and RH change trends and a bar graph expressing the PI values, this study examined the current status of the conservation environment inside the WCHs throughout the year and its diagnosis. Consequently, at higher latitudes, the organic cultural heritage repeatedly experienced large T fluctuations, and the risk of physical and chemical degradation of the materials was greater. However, the RH showed significant seasonal differences, even within the same latitude, indicating that the impact of latitude was not significant. Therefore, the staff in charge must manage RH by considering the surrounding environmental conditions and adjusting the internal environment of the structures. The PI values for the year-round T and RH inside the heritages were confirmed to only be a maximum of approximately 60% of the environmental suitability for conservation throughout the year, depending on the season. The relationship between the germination and growth potential period of xerophilic fungi and the monthly internal temperature and humidity in five heritages located at different latitudes was analyzed. As a result, we could thus determine that four particular months of the year (June-September) represent the periods with the highest risk of damage from xerophilic fungi in the country, regardless of latitude.

• Journal of KIISE:Databases
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• v.29 no.3
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• pp.193-206
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• 2002

In this paper, we design and implement an efficient bulk-loading algorithm for CIR-Tree. Bulk-loading techniques increase node utilization, improve query performance and reduce index construction time. The CIR-tree has variable size of internal node entries since it only maintains minimal dimensions to decriminate child nodes. This property increases fan-out of internal nodes and improves search performance. Even though several bulk-loading algorithms for multi/high-dimensional index structures have been proposed, we cannot apple them to CIR-tree because of the variable size of internal node entries. In this paper, we propose an efficient bulk- loading algorithm for CIR-tree that improves the existing bulk-loading algorithm and accomodates the property of CIR-tree. We also implement it on a storage system MiDAS-III and show superiority of our algorithm through various experiments.

• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.159-160
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• 2006

This paper discusses sensitivity analysis for determining adequate locations of series-type FACTS devices. The main objective of FACTS reinforcement is to alleviate line over-loadings against violation of thermal limits after disturbances. This paper, to obtain the information concerning series-type FACTS locations, proposes a formulation for the sensitivity of the PI (Performance Index) with respect to the variation of the branch parameters, and applies to 5-bus test system to show the effectiveness of the sensitivity.

• Proceedings of the KIEE Conference
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• 1999.07b
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• pp.815-817
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• 1999

In the two-mass system driving a load through a flexible shaft or transmission system, a shaft torsional vibration is often generated. In this case, it's difficult to control only by conventional PI controller. To solve this problem. the two-mass speed control system with PID controller is designed by using pole assignment method, and an optimum PID parameters are derived by evaluating ITAE(Integral of time multiplied by the absolute error) performance index. Simulation results show the validity of the proposed PID controller and this controller is compared with the conventional PID controller.