• Asian-Australasian Journal of Animal Sciences
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• v.30 no.2
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• pp.267-274
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• 2017

Objective: The objective of this study was to investigate the effect of 20-day litter weight on behavior and heart rate variability (HRV) of piglets under stress. Methods: Forty four original litters were categorized as high litter weight (HW) litters (n = 22) and low litter weight (LW) litters (n = 22) by 20-day litter weight. From each original HW litter, three males and three females were randomly selected after weaning and the 12 piglets from two original litters with similar age of days were regrouped into one new high litter weight (NHW) litter (11 NHW litters in total). The original LW litters were treated with a same program, so that there were 11 new low litter weight (NLW) litters as well. The latencies to first fighting, fighting frequencies and duration within three hours were recorded after regrouping and the lesions on body surface within 48 hours were scored. Besides, HR (heart rate, bpm, beats per minute) and activity count (ACT), time domain indexes and frequency domain indexes of the piglets were measured in an isolation trial to analyze the discrepancy in coping with stress between the original HW and LW litters. Results: The results exhibited that piglets from the HW litters launched fighting sooner and got statistically higher skin lesion score than those from the LW litters (p = 0.03 and 0.02, respectively). Regarding the HRV detection, compared with the HW litters, the LW litters exhibited a lower mean HR (p<0.05). In the isolation test, a highly significant higher ACT value was observed between the HW litters, compared to the LW litters (p<0.01). Significant differences were observed in standard deviation of R-R intervals, standard deviation of all normal to normal intervals, and most frequency-domain indicators: very low-frequency, low-frequency, and high frequency between the HW and LW litters as well. The difference in LF:HF was not significant (p = 0.779). Conclusion: This study suggests that compared with litters of low 20-day litter weights, litters with higher 20-day litter weight take more positive strategies to cope with stress and have stronger HRV regulation capacity; HW litters demonstrate better anti-stress and adaptation capacity in the case of regrouping and isolation.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.3
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• pp.304-311
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• 2014

In this study, to apply hydrogen energy to ship engine and to generate effective hydrogen production, we investigated the effects of high temperature $H_2SO_4$ feed rate and cooling water rate to pump parts with fixed frequency needed to reciprocate motion and a simulation was conducted at each condition. In the fixed frequency and cooling water inlet flow rate of 0.5 Hz and 3.9 kg/s, we changed the high temperature $H_2SO_4$ flow rate to 47.46 kg/s (it is 105 % of 45.2 kg/s), 49.72 kg/s (110 %), and 51.98 kg/s (115 %). Also, at 0.5 Hz and 45.2 kg/s of frequency and high temperature $H_2SO_4$ flow, the thermal hydraulic analysis was performed at the condition of 95 % (3.705 kg/s), 90 % (3.51 kg/s), and 85 % (3.315 kg/s). In overall simulation cases, the physical properties of materials are more influential to the temperature increase in the pump part rather than the changes on the feed rate of high temperature $H_2SO_4$ and cooling water. A continuous operation of pump was also capable even if the excess feed of high temperature $H_2SO_4$ of about 15 % or the less feed of cooling water of about 15 % were performed, respectively. When the increasing feed of high temperature $H_2SO_4$ of up to 5 %, 10 %, and 15 % were compared with base flow (45.2 kg/s), the deviation of time period rose to a certain temperature and ranged from 0 to 4.5 s in the same position (same material). In case of cooling water, the deviation of time period rose to a certain temperature and ranged from 0 to 5.9 s according to the decreasing feed changes of cooling water at 5 %, 10 %, and 15 % compared to a base flow (3.9 kg/s). Finally, the additional researches related to the two different materials (Teflon and STS for Pitch and End-plate), which are concerned about the effects of temperature changes to the parts contacting different materials, are needed, and we have a plan to conduct a follow-up study.

• Journal of Biomedical Engineering Research
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• v.32 no.2
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• pp.177-184
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• 2011

In this study, the system for application of the bone stimulation was implemented using high frequency and low strain method. The whole system consists of the high frequency and low strain vibration stimulation system 177 for stimulating bone, LVDT sensor, and wireless sensor based on tri-axial accelerometer. To evaluate the usefulness of the system, the frequencies and accelerations from function generator were applied to the vibration stimulation system. The range of frequency was 17 Hz, 30 Hz, 45 Hz, 50 Hz and the range of acceleration was set 0.3 g, 0.6 g, 1g, and 2 g. The measured frequencies and acceleration using LVDT (linear variable difference transformer) sensor and 3-axial accelerometer were estimated and compared. The range of frequencies average difference was from 0.0 to 0.004 Hz. As the standard deviation of frequencies estimated by LVDT sensor and accelerometer was below 0.03 Hz and the output frequencies of function generator were similar: Also the results of t-test were satisfied with conditions of p > 0.05. And the acquired frequencies and acceleration from vibration measuring device module were estimated and analyzed. As the mean of accelerations was similar to the acceleration applied from function generator. And the standard deviation of acceleration estimated from vibration measuring device module was ranged from 0.019 g to 0.038 g. Also the results of t-test were satisfied with conditions of p > 0.05. Therefore, these results were airy similar to the acceleration applied from function generator. As a result, the usefulness of the system was confirmed. n a further study, clinical experiment will be carried out with the authorization of IRB (institutional review board) so that appropriate frequency and strain would be investigated in clinical field.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.49 no.3
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• pp.95-106
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• 2000

The load frequency control of power system is one of important subjects in view of system operation and control. That is even though the rapid load disturbances were applied to the given power system, the stable and reliable power should be supplied to the users, converging unconditionally and rapidly the frequency deviations and the tie-line power flow one on each area into allowable boundary limits. Nonetheless of such needs, if the internal parameter perturbation and the sudden load variation were given, the unstable phenomenal of power system can be often brought out because of the large frequency deviation and the unsuppressible power line one. Therefore, it is desirable to design the robust neuro-fuzzy controller which can stabilize effectively the given power system as soon as possible. In this paper the robust neuro-fuzzy controller was proposed and applied to control of load frequency over multi-area power system. The architecture and algorithm of a designed NFC(Neuro-Fuzzy Controller) were consist of fuzzy controller and neural network for auto tuning of fuzzy controller. The adaptively learned antecedent and consequent parameters of membership functions in fuzzy controller were acquired from the steepest gradient method for error-back propagation algorithm. The performances of the resultant NFC, that is, the steady-state deviations of frequency and tie-line power flow and the related dynamics, were investigated and analyzed in detail by being applied to the load frequency control of multi-area power system, when the perturbations of predetermined internal parameters. Through the simulation results tried variously in this paper for disturbances of internal parameters and external stepwise load stepwise load changes, the superiorities of the proposed NFC in robustness and adaptive rapidity to the conventional controllers were proved.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.5
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• pp.622-628
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• 2014

This paper presents the SOC-based control strategy of BESS(Battery Energy Storage System) for providing power system frequency regulation in the bulk power systems. As the life cycle of BESS would be shortened by frequent changes of charge and discharge required for frequency regulation in a steady state, the proposed algorithm operates BESS within a range of SOC where its life cycle can be maximized. However, during a transient period of which occurrence frequency is low, BESS would be controlled to use its full capacity in a wider range of SOC. In addition, each output of multiple BESS is proportionally determined by its SOC so that the balance in SOC of multiple BESS can be managed. The effectiveness of the proposed control strategy is verified through various case studies employing a test system. Moreover, the control result of BESS with the measured frequency from a real system shows SOC of BESS can be maintained within a specific range although the frequency deviation is biased.

• Journal of Electrical Engineering and Technology
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• v.12 no.2
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• pp.937-943
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• 2017

To design an automatic steering controller with high performance for autonomous vehicle, it is necessary to have a precise model of the lateral dynamics with respect to the steering command input. This paper presents an empirical modeling of the steering system for an autonomous vehicle. The steering system here is represented by three individual transfer function models: a steering wheel actuator model from the steering command input to the steering angle of the shaft, a dynamic model between the steering angle and the yaw rate of the vehicle, and a dynamic model between the steering command and the lateral deviation of vehicle. These models are identified using frequency response data. Experiments were performed using a real vehicle. It is shown that the resulting identified models have been well fitted to the experimental data.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.54 no.7
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• pp.343-350
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• 2005

Conventionally, for transferring the primary power to the secondary one, the high frequency series resonant converter has been widely used for the contactless power supply system. However, the high frequency series resonant converter has the disadvantages such as the low efficiency, the high voltage gain characteristics and deviation of the phase angle in the overall load range. To improve this disadvantages, In this paper, the characteristics of the high efficiency and unit voltage gain as well as in-phase are revealed in the proposed three-level LCLC (Inductor-Capacitor- Inductor-Capacitor) resonant converter. The results are verified on the simulation based on the theoretical analysis and the 4kW experimental Prototype.

• Journal of Families and Better Life
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• v.16 no.2
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• pp.83-96
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• 1998

The purpose of this study was to investigate the level of assets and liabilities of farm households and to evaluate the financial status of rural middle-aged and old-aged household using financial ratios. For these purposes an empirical survey data was gathered from rural middle-aged and old-aged households in 8 provinces using structured questionnaires. 877 households data were used in final analysis. The statistical methods used for data analysis are frequency percentile mean The statistical methods used for data analysis are frequency percentile mean median standard deviation $\chi$2 and t-test using SPSS/PC WIN program. Among financial ratios 64.7% of total households could meet the guideline of consumption to income ratio 5.9% of total households could meet the appropriate level of short-term and long-term liquidity. In the case of debt burden ration 82% of total households could meet the guideline. And 28.5% of total households could meet the guideline of capital stock ratio .

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.1
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• pp.101-106
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• 2004

The phenomenon of PD(Partial Discharge) is accompanied by electromagnetic wave which can be detected by UHF(Ultra High Frequency) antenna. The signals obtaining from UHF antenna are very high rapid pulse and have wide band frequency responses. The distribution of PRPD(Phase Resolved Partial Discharge) which consisted of those pulse train can show distinct characteristics of PD sources. But it is not sufficient to discriminate among PD sources. This paper suggests that the stochastic parameters formed by preprocessing of STFT(Short Time Fourier Transform) are good tools for differentiate from PD sources. The stochastic parameters are CC(Cross Correlation) mean value, CC standard deviation, CC skewness, CC kurtosis.

• Proceedings of the KSRS Conference
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• 2004.10a
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• pp.121-124
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• 2004

This paper proposed the method of creating image mosaic in automated fashion. It is well known that geometric and radiometric balance in adjacent images should be maintained in mosaicking process. The seam line to minimize geometric discontinuity was extracted using Minimum Absolute­Gray-Difference Sum considering constraint condition in search width. To maintain the radiometric balance of images acquired at different time, we utilized Match Cumulative Frequency, Match Mean and Standard Deviation and Hue Adjustment algorithm. The mosaicked image prepared by the proposed method was compared with those of commercial software. Experiments show that seam lines were extracted significantly well from roads, rivers. ridgelines etc. and Match Cumulative Frequency algorithm was performed pretty good in histogram matching