• Korean Journal of Applied Biomechanics
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• v.14 no.1
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• pp.133-144
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• 2004

The purpose of this study was to analyze the joint moment on lower extremity during a developpe devant. Data were collected by Kwon3D, KwonGRF program. Two professional modem female dancers were participated in this experiment. Subjects performed a developpe devant in meddle heights. On the axes of X, Y, Z, it was shown that the maximum joint moment was occurred in hip joint. The moments are plotted during developpe devant. The ankle muscles generate a plantar flexion moment and the knee muscles generate a flexion moment and The hip muscles generate a extension moment. So these muscles of joint muscles were known to play a key role in keeping the body balance while doing developpe devant. In addition adduction moment occurred at hip, knee, an ankle in the order of amount, we could assume from this data that him out motion started from the hip joint. There was small active turn out possible below the hip joint. A small amount of extra turn out could be obtained when standing because of flexion between the foot and floor, which could be used to give a passive external rotation force to the whole leg and this could produce a rotation between the knee and foot. This passive external rotation could produce very damaging results. Therefore, lower extremity joint muscles such as hip, knee, and ankle muscle should be trained to keep the body balance and prevent injury during developpe devant performance. And for the safe and perfect turn ort performance, hip joint abduction, the most important external rotating muscle for him out is needed to train and full stretching should be done in advance.

• The Transactions of the Korean Institute of Power Electronics
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• v.15 no.3
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• pp.167-178
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• 2010

To diagnose a stator winding fault caused by a short-circuited turn in a permanent magnet synchronous motor (PMSM), an on-line based fault detecting scheme during motor operation is presented. The proposed scheme is based on monitoring the second-order harmonic components in q-axis current obtained through the harmonic analysis and a winding fault is detected by comparing these components with those in normal conditions. The linear interpolation method is employed to determine harmonic data in arbitrary normal operating conditions. To verify the effectiveness of the proposed fault detecting scheme, a test motor to allow inter-turn short in the stator winding has been built. The entire control system including harmonic analysis algorithm and fault detecting algorithm is implemented using DSP TMS320F28335. The proposed scheme does not require any additional hardware and can effectively detect a fault during motor operation so long as the steady-state condition is satisfied.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.49 no.5
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• pp.37-42
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• 2012

In this paper, a new charge pump is proposed to reduce the timing mismatch in the conventional current-steering charge pumps. Conventional current-steering charge pumps used NMOS input stages both for UP and DOWN signals, which resulted in different numbers of stage for UP and DOWN delay paths. The proposed charge pump has equalized the numbers of stages for UP and DOWN signals by using a PMOS stage for the DOWN signal. The simulation results show that the conventional current-steering charge pump has 14ns and 6ns for optimized timing mismatches between UP and DOWN signals for turn-on and turn-off, respectively. On the other hand, the proposed charge pump has improved timing mismatches of 6ns and 5ns for turn-on and turn-off, respectively. As a result, the reference spurs are reduced from -26dBc to -39dBc for the proposed charge pump. The proposed charge pump was designed by using $0.18{\mu}m$ CMOS technology. The measurement results show that the maximum variation of the charging and discharging current over the charge pump output voltage range of 0.3~1.5V is approximately 1.5%.

• Korean Journal of Materials Research
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• v.10 no.4
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• pp.301-304
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• 2000

A new triode type Co-silicided Si FEA(field emitter array) was realized by Co-silicidation of Co coated Si FEA and its field emission properties were investigated. The field emission properties of the fabricated device through the unit pixel with $45{\times}45$ tip array in the area of $250{\mu\textrm{m}}{\times}250{\mu\textrm{m}}$ under high vacuum condition of $10^{-8}Torr$ were as follows : the turn-on voltage was about 35V and the anode current was about $1.2\mu\textrm{A}(0.6㎁/tip)$ at the bias of $V_A=500V\;and\; V_G=55V$. The fabricated device showed the stable electrical characteristics without degradation of field emission current for the long term operation except for the initial transient state. The low turn-on voltage and the high current stability of the Co-silicided Si FEA were due to the thermal and chemical stability and the low work function of silicide layer formed at the surface of Si tip.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.3
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• pp.510-518
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• 2014

In this study, in order to improve and optimize the performance of the turning mechanism for a fish robot in the fluid, we propose the tail joint trajectories using neural networks to mimic the CST(C-shape Sharp Turn) patterns of a real fish which is optimized in the natural environment. In order to mimic the CST patterns of a fish, we convert the sequential recording CST patterns into the coordinate data, and change the numerical coordinate data into a functions. We change the motion functions to the relative joint angles which is adapted to suit robot's shape and data. However, these relative joint trajectories obtained by the sequential recording of the carp have low-precision. It is difficult to apply to the control of a fish robot. Therefore, the relative joint trajectories are interpolated using neural networks with superior generalization ability and applied to the fish robot. we have found that the proposed method using neural networks is superior to ones using high-order polynomial equation through the computer simulations.

• The Transactions of the Korean Institute of Power Electronics
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• v.16 no.3
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• pp.242-249
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• 2011

The proposed converter has easy device selection for high step-up and high power applications since boost half bridge and voltage doubler cells are connected, respectively, in parallel and series in order to increase output power and voltage. Especially, optimized design of high frequency transformers is possible owing to reduced turn ratio and eliminated dc offset, and distributed power through three cores is beneficial to low profile and thermal distribution. The proposed converter does not necessitate start-up circuit and additional clamp circuit due to the use of whole duty range between 0 and 1 and is suitable for applications with wide input voltage range. Also, high efficiency can be achieved since ZVS turn on of switches are achieved in wide duty cycle range and ZCS turn on and off of diodes are achieved. The proposed converter was validated through 5 kW prototype.

• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.6
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• pp.127-134
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• 2011

It has been reported that the length parameter of high strength bolts results in the variance in tensile loads. The required turn of nut for each length is specified in AISC RCSC specification. There is no specific regulation datum about the bolt length in the two national codes and specifications in Korea. Therefore this study focused on evaluating influence of the clamping torque subjected to length parameter of high strength bolts. Two types of high strength bolt specimens were manufactured and tested; High Strength Hexagon bolt specified in ASTM A490 and Torque Shear Bolt in KS B 2819. The length parameter ranged from 60mm(3d) to 140mm(7d). The torque, turn of nut, and the clamping force were analyzed to review whether length parameter affects on the required tensile strength. To evaluate the effects of the length parameter on the torque and turn of nut for the required strength and clamping force, statistical analysis was also carried out.

• Restorative Dentistry and Endodontics
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• v.18 no.1
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• pp.84-94
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• 1993

The purpose of this study was to evaluate flexure strength of composite resin inlay according to heat treatment and duration in comparasion with visible light-cured resin. In this study, materials were used 1 visible light-cured resin and 3 kinds of composite resin inlays. Control group was visible light cured resin (Photo Clearfil Posterior) and experimental groups were composite resin inlays (Brilliant Dentin, Brilliant Enamel and Clearfil CR Inlay). Experimental groups were divided 3 groups: First group was Brilliant Dentin and second group was Brilliant Enamel and -third group was Clearfil CR Inlay. Used experimental groups were calculated flexural strength according to heat treatment and duration. The following results were obtained: 1. Experimental groups were higher flexural strength than control group. 2. At $100^{\circ}C$ when heat treatment carried out 7 minutes flexural strength elevated third group, second group, first group in turn and when heat treatment carried out 15 minutes flexural strength elevated third group, second group, first group in turn but no difference was showed between first and second group. 3. At $125^{\circ}C$ when heat treatment was carried out 7 minutes flexural strength elevated third group, second group, first group in turn and when heat treatment was carried out 15 minutes flexural strength elevated third group, first group, second group in turn but no difference was showed between first and second group. 4. In spite of heat treatment and duration the third group was highest flexural strength in the others groups.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.623-626
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• 2005

Toward the practical applications, on operation of conduction-cooled HTS SMES at temperatures well below 77 K should be investigated, in order to take advantage of a greater critical current density of HTS and considerably reduce the size and weight of the system. Recently, research and development concerning application of the conduction-cooled HTS SMES that is easily movement are actively progressing in Korea. Electrical insulation under cryogenic temperature is a key and an important element in the application of this apparatus. Using multi wrapped copper by polyimide film for HIS SMES, the breakdown characteristics of models for turn-to-turn, that is surface contact model, were investigated under ac and impulse voltage at 77 K. A material that is Polyimide film (Kapton) 0.025 mm thickness is used for multi wrapping of the electrode. Statistical analysis of the results using Weibull distribution to examine the wrapping number effects on breakdown voltage under ac and impulse voltage in $LN_2$ was carried.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.14 no.1
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• pp.46-56
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• 2015

The purpose of this study is to find out the effectiveness of drivers' satisfaction over protected and permissive left-turn (PPLT) traffic signal operation. A structural equation model was established for analyzing the effectiveness of various drivers' factors (e.g., personal characteristics, driving attitude, expectation to PPLT, etc.) on the PPLT preference based on questionnaire survey. As a result, the analysis is satisfied with the critical values, such as Q value, RMR, GIF, AGIF, and NFI. The study reveals that PPLT preference increases in case of driver who is male with long social carrier related to transportation affaire and long driving experience without traffic accident involvement. Moreover, PPLT preference increases as the expectation of PPLT to improvement of traffic safety, traffic operation, and traffic environment increases. Therefore, it is recommended that the PPLT should be preferentially operated in urban area of less traffic accidents and the promotion of PPLT be actively conducted for positive effectiveness.