• Nuclear Engineering and Technology
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• v.51 no.4
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• pp.963-967
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• 2019

Accurate measurement of the reactivity worth of safety rods is very important for the safe reactor operation, in normal and emergency conditions. In this paper, the reactivity worth of safety rods in Heavy Water Zero Power Reactor (HWZPR) in the new lattice pitch is measured by advanced source jerk method. The average of the results related to two different detectors is equal to 29.88 mk. In order to verify the result, this parameter was compared to the previously measured value by subcritical to critical approach. Different experiment results are finally compared with corresponding calculated result. Difference between the average experimental and calculated results is equal to 2.2%.

• Journal of Advanced Navigation Technology
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• v.20 no.3
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• pp.246-251
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• 2016

This paper has optimized WPT (wireless power transfer) antenna, and compared EM (electromagnetic) simulation result with measurement for the magnetic resonant type standard of A4WP (alliance for wireless power) using 6.78MHz frequency and 1m distance. Power transmission distance is affected by various factors such as system shape, antenna size, and resonator coil pitch etc, which were confirmed by the EM simulation. By simulation an optimized WPT antenna was designed for a fixed distance, and the transmission loss ${\mid}S_{21}{\mid}$ has been calculated with changing distance. Measurement was carried for the fabricated antenna, and the measured transmission loss is 1.5dB with 70% efficiency at maximum 1.3m distance compared to the simulated loss of 1.6dB with 69% efficiency

• International Journal of Highway Engineering
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• v.7 no.4 s.26
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• pp.125-140
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• 2005

This study suggests a suitable random transverse tining for reduction tire/road noise from concrete pavement. Through literature reviews, random transverse tining that can disperse the energy concentrated to the specific frequency was suggested using the LCG(linear congruential generators) algorithm. The spacing of tining from this study is applied to Daegu-Pohang express highway. For the purpose oi comparison, two other random tining sections were included that are research products from Chung-Ang university and Wisconsin DOT. In result of pass-by noise measurement by car, though designed section is superior to the others as noise reduction by reducing pitch noise, the effectiveness is not large. In case of traffic noise measurement, lower noise was observed at random transverse tining sections than uniformly transverse tining section, too. But there are seine differences between pass-by noise and traffic noise.

• Journal of the Ergonomics Society of Korea
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• v.35 no.5
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• pp.319-341
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• 2016

Objective:This research analyzed the lower-limb motion in kinetic and kinematic way while walking on various terrains to develop Foot-Ground Contact Detection (FGCD) algorithm using the Inertial Measurement Unit (IMU). Background: To estimate the location of human in GPS-denied environments, it is well known that the lower-limb kinematics based on IMU sensors, and pressure insoles are very useful. IMU is mainly used to solve the lower-limb kinematics, and pressure insole are mainly used to detect the foot-ground contacts in stance phase. However, the use of multiple sensors are not desirable in most cases. Therefore, only IMU based FGCD can be an efficient method. Method: Orientation and acceleration of lower-limb of 10 participants were measured using IMU while walking on flat ground, ascending and descending slope and stairs. And the inertial information showing significant changes at the Heel strike (HS), Full contact (FC), Heel off (HO) and Toe off (TO) was analyzed. Results: The results confirm that pitch angle, rate of pitch angle of foot and shank, and acceleration in x, z directions of the foot are useful in detecting the four different contacts in five different walking terrain. Conclusion: IMU based FGCD Algorithm considering all walking terrain possible in daily life was successfully developed based on all IMU output signals showing significant changes at the four steps of stance phase. Application: The information of the contact between foot and ground can be used for solving lower-limb kinematics to estimating an individual's location and walking speed.

• Korean Journal of Optics and Photonics
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• v.5 no.1
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• pp.138-143
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• 1994

A speckle correlation method was applied to measure the in-plane translation of a diffuse object which has rough surface using a linear CCD sensor and personal computer. Displacement of a speckle pattern produced from the object illuminated by a laser beam was measured by the cross-correlation functions between the I-D speckle profiles before and after the object translation, which were measured by linear CCD array sensor to be sent to IBM 386 personal computer. The sensitivity of the measurement was dependent on the radius of the wavefront curvature of incident beam as well as the spatial resolution of linear CCD array. A linear CCD array had 15 Jlffi pitch and 1728 pixels. The ratio of the speckle displacement and object translation varied from 1.03 to 5.20. The object translation of $3\mu\textrm{m}$ can be measured br the linear CCD sensor of which pitch was $15\mu\textrm{m}$, when the ratio of the speckle displacement and object translation was 5.20.s 5.20.

• Speech Sciences
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• v.9 no.4
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• pp.187-200
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• 2002

The purpose of the present study is to see in terms of $F_{0}$ variation in Japanese how discourse focus and the lexical word accent interact with each other in realizing overall intonation patterns. Discourse focus causes prosodic restructuring of phrase structures and, as a result, largely affects pitch contours, whereas the lexical word accent is said to delimit the $F_{0}$ into a certain range. Measurement of $F_{0}$ was made of utterances of Japanese sentences to observe behavior of pitch contours with varied focus assignment and lexical accent specifications. The utterances were obtained in question-answer discourse contexts so that in a sentence, either one NP was always focused or no focus was assigned. I set four points for $F_{0}$ measurement; $F_{1s},F_{1m}, F_{2s}$, and $F_{2m}$, two for each noun phrase corresponding to $F_{0}$ at the beginning of the first syllable and that of the vocalic portion of the second syllable in the two NP's. The results of present study were as follows: (1) for all combination of lexical accent types, the $F_{0}$ rise both in NP1 and NP2 are higher when focused than when not focused. (2) NP2 starts a new accentual phrase when focused, showing even higher $F_{0}$ than NP1, the latter of which implies that in forming a new accentual phrase by focusing, catathesis does not seem to take effect on NP2 preceded by accented NP1. (3) unfocused NP2 preceded by unaccented NP1 has higher $F_{0}$ than those preceded by accented NP1.

• Journal of Radiation Protection and Research
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• v.30 no.3
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• pp.113-119
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• 2005

The computed tomogrpahy(CT) provides a high quality in images of human body but contributes to the relatively high patient dose. The frequency of CT examination is increasing and, therefore, the concerns about the patient dose are also increasing. In this study the experimental determination of patient dose was performed by using a physical anthropomorphic phantom and thermoluminescent dosimeter(TLD). The measurements were done for the both axial and spiral scan mode. As a result the effective doses for each scan mode were 17.78mSv and 10.01 mSv respectively and the fact that the degree of the reduction in the patient dose depends on the pitch scan parameter was confirmed. The measurement methods suggested in this study can be applied for the reassessment of the patient dose when the technique in CT equipment is developed or the protocol for CT scanning is changed.

• Current Research on Agriculture and Life Sciences
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• v.32 no.3
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• pp.159-163
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• 2014

Agricultural unmanned helicopters have become a new paradigm for aerial application. Yet, such agricultural helicopters require easy and affordable attitude control systems. Therefore, this study presents an affordable attitude measurement system using a DCM (direction cosine matrix) algorithm that would be applied to agricultural unmanned helicopters. An IMU using a low-cost MEMS and an algorithm to estimate the attitude of the helicopter were applied in a gimbals structure to evaluate the accuracy of the attitude measurements. The estimation errors in the attitude were determined in comparison with the true angles determined by absolute position encoders. The DCM algorithm and sensors showed an accuracy of about 1.1% for the roll and pitch angle estimation. However, the accuracy of the yaw angle estimation at 3.7% was relatively larger. Such errors may be due to the magnetic field of the stepping motor and encoder system. Notwithstanding, since the intrinsic behavior of the agricultural helicopter remains steady, the determination of attitude would be reliable and practical.

• Polymer(Korea)
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• v.36 no.6
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• pp.756-760
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• 2012

In this work, the coal tar pitch-based activated carbons (ACs) were prepared by KOH activation for electrode materials of supercapacitor. The effects of activation temperature on electrochemical performance of the ACs were investigated with cyclic voltammogram (CV) measurement. The textural and morphological properties of the ACs were measured by adsorption isotherms and field emission scanning electron microscope (FE-SEM) analyses, respectively. The experimental results indicated that the specific capacitance of the ACs increased with developing the micropore volume by activation temperature. As a result the specific capacitance of the ACs increased, owing to the development of micro pore volume of the ACs.

• Phonetics and Speech Sciences
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• v.3 no.4
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• pp.63-70
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• 2011

Recent studies on English $L^*$ (low pitch accent) have revealed the difference of changes in acoustic manifestation between utterances produced by Koreans and those produced by native speakers of English. However, not much effort has been made to compare $L^*$ focused constituents and non-focused constituents. At the same time, most previous works on focus realization are lacking in terms of normalization of acoustic measurement. Therefore, this research is dedicated to comparing the $L^*$ focused items and non-focused items realized by Koreans and Americans and to examining the realization of English $L^*$ produced by the two language groups with improved normalization of the acoustic features (F0, intensity and duration). Within-group analysis comparing focused words and non-focused words showed both Americans and Koreans prolonged the $L^*$ focused syllables but the effect size of syllable lengthening made by Koreans was far less than that made by Americans. Furthermore, significant F0 lowering was found in Americans but not in Koreans. However, the effect of intensity change caused by $L^*$ focus was not significant within each group. The effect of focused words was tested between the two groups revealing that Koreans implemented English $L^*$ focus with higher F0, lower intensity and shorter duration than Americans. In the instances in which a significant Group x Focus Location (initial, middle and final of a sentence) interaction was found, further analysis testing the effect of Group on each Focus Location was conducted. The testing showed that the Koreans produced shorter syllables at initial and middle of a sentence and higher F0 at initial of a sentence than Americans. Implications for the intonation training were also discussed.