• The KSFM Journal of Fluid Machinery
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• v.7 no.2 s.23
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• pp.27-34
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• 2004

The performance of a centrifugal compressor composed of an impeller, tandem diffuser rows and axial guide vanes has been predicted numerically and compared with available experimental results on its design rotational speed. The pitchwise-averaged mixing plane method was employed for the boundaries between rotor and stator to obtain steady state solutions. The overall characteristics showed difference according to the relative positions of tandem diffuser rows while the characteristics of impeller showed almost identical result. The numerical results agree with the measured data in respect of their tendency. It turned out that $0\%$ of relative positions is the worst case in terms of static pressure recovery and efficiency. According to the experimental results, some pressure fluctuations and malfunction of the compressor were observed for $75\%$ case. However, this numerical calculation using mixing plane method did not capture any of those phenomena. Thus, unsteady flow calculation should be performed to investigate the stability of the compressor caused by different diffuser configuration.

• Korean Journal of Oriental Medicine
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• v.18 no.2
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• pp.47-54
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• 2012

Objective : This study was designed to analyze the results of autonomic nervous activity(ANA) and autonomic nervous balance(ANB) by heart rate variability test. The subjects were workers in the automobile manufacturing company. Method : The subjects consisted of 32,049 workers who had answered about questionnaires of a job position, age, smoking, drinking, exercise history and sex. The ANA and ANB were examined by SA3000P. I analyzed the differences of ANA and ANB according to job positions, ages, the state of smoking, drinking, exercise and sex by T-test or ANOVA with SPSS ver. 17.0. Results : Regarding the differences of ANA among job positions, the ANA was lowest in sales positions, highest in production workers. Among ages, the ANA was highest in 50s, lowest in 30s. In smoking, the ANA was higher in non-smoking group. In drinking, the ANA was higher in non-drinking group. In exercise, the ANA was higher in exercise group. In sex, there was no significant difference. The case of ANB, there were no significant differences except for ages. Among ages, the ANB was highest in 20s, the lowest in 40s. Conclusion : According to these results, we should establish the methods of controlling ANA and ANB from the perspective of Korean traditional medicine.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.59 no.2
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• pp.222-231
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• 2010

This paper presents numerical analysis of measurement errors of ground electrode using the fall-of-potential method. In order to analyze ground resistance error according to the positions of auxiliary probes, firstly, national and international standards were researched. Secondly, numerical ground resistance error of hemispheric electrode was analyzed according to the locations of auxiliary probes and the angle between probes. Then, error-reduced positions of auxiliary probes were shown according to the distance to auxiliary current probe versus ground electrode size. Finally, error compensation method was presented. The results presented in this paper provide useful information regarding ground resistance error of alternative positions of auxiliary probes in case that the auxiliary probes could not be located at the proper position in such cases as there are buildings, roadblock or underground metallic pipe at that position.

• Journal of the Korean Society of Physical Medicine
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• v.6 no.4
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• pp.397-406
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• 2011

Purpose : Recently ultrasound images has been used to measure the subacromial space with a linear measurement of the acromiohumeral distance. The purpose of this study was to comparison of distance of subacromial space using ultrasonographic measurement on arm positions of shoulder injured patients. Methods : The subjects were 30 shoulder injured patients (19 males and 11 females). Ultrasonography was performed to measure subacromial space during each shoulder resting position, $45^{\circ}$ abduction, internal rotation with $45^{\circ}$ abduction and external rotation with $45^{\circ}$ abduction. Results : Subacromial space was a significantly difference between injured arm and normal arm at shoulder resting position. At $45^{\circ}$ abduction, subacromial space was narrowing significantly between injured arm and normal arm. At external rotation with $45^{\circ}$ abduction, subacromial space were wider in normal arm than in injured arm but it was not significantly. Intra-observer reliability for ultrasonography measurement of subacromial distance was excellent (.96~.99). Conclusion : These results identified that positions of injured shoulder was related to subacromion space.

• Journal of Microbiology and Biotechnology
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• v.18 no.6
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• pp.1044-1049
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• 2008

In order to study functional nucleotides in prototype foamy virus (PFV) DNA on specific recognition by PFV integrase (IN), we designed chimeric U5 long terminal repeat (LTR) DNA substrates by exchanging comparative sequences between human immunodeficiency virus type-1 (HIV-1) and PFV U5 LTRs, and investigated the 3'-end processing reactivity using HIV-1 and PFV INs, respectively. HIV-1 IN recognized the nucleotides present in the fifth and sixth positions at the 3'-end of the substrates more specifically than any other nucleotides in the viral DNA. However, PFV IN recognized the eighth and ninth nucleotides as distinctively as the fifth and sixth nucleotides in the reactions. In addition, none of the nucleotides present in the twelfth, sixteenth, seventeenth, eighteenth, nineteenth, and twentieth positions were not differentially recognized by HIV-1 and PFV INs, respectively. Therefore, our results suggest that the functional nucleotides that are specifically recognized by its own IN in the PFV U5 LTR are different from those in the HIV-1 U5 LTR in aspects of the positions and nucleotide sequences. Furthermore, it is proposed that the functional nucleotides related to the specific recognition by retroviral INs are present inside ten nucleotides from the 3'-end of the U5 LTR.

• Journal of Biosystems Engineering
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• v.16 no.2
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• pp.118-123
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• 1991

This study was conducted to investigate the influences of virtual hitch point (VHP) positions of a three-point hitch on the steering stability of agricultural tractors. The VHP locations were determined analytically from the linkage geometry and implement posture during the normal tillage operations. The maximum force applicable to the VHP was also determined under the given soil and power constraints. From these possible ranges of the VHP locations, a safe region for steering control was determined theoretically by using maximum applicable forces for the given tractor and implement combinations. With VHP positions within the safe region, tractor can maintain the minimum soil reaction forces, assumed 20% of the total tractor weight in this study, at the front wheels which is required for the steering control under the maximum traction conditions. This paper mainly concerns with mathematical developments for the determination of VHP locations and maximum forces applicable to the VHP for steering control. Experimental validation of the theory developed here follows as the second part of this study.

• Industrial Engineering and Management Systems
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• v.6 no.1
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• pp.40-48
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• 2007

This study investigated the optimum positions and warning foreperiod for auditory signals with an experiment on spatial stimulus-response (S-R) compatibility effects. The auditory signals were presented at the front-right, front-left, rear-right, and rear-left positions from the subjects, whose reaction times and accuracies at different spatial mapping conditions were examined. The results showed a significant spatial stimulus-response compatibility effect in which faster and more accurate responses were obtained in the transversely and longitudinally compatible condition while the worst performance was found when spatial stimulus-response compatibility did not exist in either orientation. It was also shown that the transverse compatibility effect was found significantly stronger than the longitudinal compatibility effect. The effect of signal position was found significant and post hoc test suggested that the emergent warning alarm should be placed on the front-right position for right-handed users. The warning foreperiod prior to the signal presentation was shown to influence reaction time and a warning foreperiod of 3 s is found optimal for the 2-choice auditory reaction task.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.8
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• pp.1250-1256
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• 2017

In this research, a high-performance ultrasonic positioning system is proposed to track the positions of an indoor mobile object. Composed of an ultrasonic sender (mobile object) and a receiver (anchor), the system employs three ultrasonic time-off-flights (TOFs) and trilateration to estimate the positions of the object with an accuracy of sub-centimeter. On the other hand, because ultrasonic waves are interfered by temperature, wind and various obstacles obstructing the propagation while propagating in air, ultrasonic pulse debounce technique and Kalman filter were applied to TOF and position calculation, respectively, to compensate for the interference and to obtain more accurate moving object position. To perform tasks in real time, ultrasonic signals are processed full-digitally with a Zynq SoC, and as a software design tool, Vivado IDE(integrated design environment) is used to design the whole signal processing system in hierarchical block diagrams. And, a hardware/software co-design is implemented, where the digital circuit portion is designed in the Zynq's fpga and the software portion is c-coded in the Zynq's processors by using the baremetal multiprocessing scheme in which the c-codes are distributed to dual-core processors, cpu0 and cpu1. To verify the usefulness of the proposed system, experiments were performed and the results were analyzed, and it was confirmed that the moving object could be tracked with accuracy of sub-cm.

• Structural Engineering and Mechanics
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• v.64 no.6
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• pp.783-792
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• 2017

Carbon Fiber Reinforced Polymer (CFRP) laminates are used widely either for repairing or strengthening of existing structures. When CFRP laminates are used for strengthening of RC continuous T-beams in the Hogging Moment Zone (HMZ); above and around the intermediate supports, it is important to study the expected positions of the laminates across the width of the beam flange. Although, it is traditional to consider CFRP laminates added above the beam web, this is not practical since walls and columns are located in such positions in general. This paper examines the effect of changing the positions of CFRP laminates used for the strengthening of the hogging moment zone across the beam flange of two-span-T-section beams. The Finite Element (FE) Package ANSYS is used to create 3-D theoretical models needed for the study. It can be concluded that changing the position of CFRP strengthening across the beam flange, in the hogging moment zone, is effective upon the overall behavior. The best locations are either above the web or at the flange just beside the web, due to the presence of walls and/or columns.

• Magazine of the Korean Society of Agricultural Engineers
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• v.40 no.2
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• pp.59-68
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• 1998

This study was conducted to derive optimal design floods by generalized gamma distribution model of the annual maximum series at eight watersheds along Geum, Yeongsan and Seomjin river systems. Design floods obtained by different methods for evaluation of parameters and for plotting positions in the generalized gamma distribution model were compared by the relative mean errors and graphical fit along with 95% confidence limits plotted on gamma probability paper. The results were analyzed and summarized as follows. 1. Basic statistics and parameters were calculated by the generalized gamma distribution model using different methods for parameters. 2. Design floods according to the return periods were obtained by different methods for evaluation of parameters and for plotting positions in the generalized gamma distribution model. 3. It was found that design floods derived by sundry averages method for parameters and Cunnane method for plotting position in the generalized gamma distribution are much closer to those of the observed data in comparison with those obtained by the other methods for parameters and for plotting positions from the viewpoint of relative mean errors. 4. Reliability of design floods derived by sundry averages method in the generalized gamma distribution was acknowledged within 95% confidence interval.