• Ocean Systems Engineering
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• 제3권4호
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• pp.275-294
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• 2013

Side-by-side offloading operations are widely utilized in engineering practice. The hydrodynamic interactions between two vessels play a crucial role in safe operation. This study focuses on the coupled effects between two floating bodies positioned side-by-side as a shuttle tanker-FPSO (floating production, storage and offloading) system. Several wave directions with different side-by-side distances are studied in order to obtain the variation tendency of the horizontal hydrodynamic coefficients, motion responses and mean drift forces. It is obtained that the coupled hydrodynamics between two vessels is evidently distinguished from the single body case with shielding and exaggerating effects, especially for sway and yaw directions. The resonance frequency and the peak amplitude are closely related with side-by-side separation distance. In addition, the horizontal hydrodynamics of the shuttle tanker is more susceptible to coupled effects in beam waves. It is suggested to expand the gap distance reasonably in order to reduce the coupled drift forces effectively. Attention should also be paid to the second peaks caused by hydrodynamic coupling. Since the horizontal mean drift forces are the most mainly concerned forces to be counteracted in dynamic positioning (DP) system and mooring system, prudent prediction is beneficial in saving consumed power of DP system and reducing tension of mooring lines.

• 전기학회논문지
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• 제65권7호
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• pp.1128-1134
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• 2016

Demand response provides customer load reductions based on high market prices or system reliability conditions. One type of demand response, price-based program, induces customers to respond to changes in product rates. However, there are large-scale general and industrial customers that have difficulty changing their energy consumption patterns, even with rate changes, due to their electricity demands being commercial and industrial. This study proposes an in-house pricing model for large-scale general and industrial customers, particularly those with multiple business facilities, for self-regulating demand-side management and cost reduction. The in-house pricing model charges higher rates to customers with lower load factors by employing peak to off-peak ratios in order to reduce maximum demand at each facility. The proposed scheme has been applied to real world and its benefits are demonstrated through an example.

• International Journal of Fluid Machinery and Systems
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• 제3권2호
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• pp.113-121
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• 2010

LES(Large Eddy Simulation) with a cavitation model was performed to calculate an unsteady flow for a mixed flow pump with a closed type impeller. First, the comparison between the numerical and experimental results was done to evaluate a computational accuracy. Second, the torque acting on the blade was calculated by simulation to investigate how the cavitation caused the fluctuation of torque. The absolute pressure around the leading edge on the suction side of blade surface had positive impulsive peaks in both the numerical and experimental results. The simulation showed that those peaks were caused by the cavitaion which contracted and vanished around the leading edge. The absolute pressure was predicted by simulation with -10% error. The absolute pressure around the trailing edge on the suction side of blade surface had no impulsive peaks in both the numerical and experimental results, because the absolute pressure was 100 times higher than the saturated vapor pressure. The simulation results showed that the cavitation was generated around the throat, then contracted and finally vanished. The simulated pump had five throats and cavitation behaviors such as contraction and vanishing around five throats were different from each other. For instance, the cavitations around those five throats were not vanished at the same time. When the cavitation was contracted and finally vanished, the absolute pressure on the blade surface was increased. When the cavitation was contracted around the throat located on the pressure side of blade surface, the pressure became high on the pressure side of blade surface. It caused the 1.4 times higher impulsive peak in the torque than the averaged value. On the other hand, when the cavitation was contracted around the throat located on the suction side of blade surface, the pressure became high on the suction side of blade surface. It caused the 0.4 times lower impulsive peak in the torque than the averaged value. The cavitation around the throat caused the large fluctuation in torque acting on the blade.

• Journal of Oral Medicine and Pain
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• 제24권1호
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• pp.37-47
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• 1999

This study was performed to investigate the factors related to vibration of temporomandibular joint during mandibular opening movement. For this study, 144 patients with temporomandibular disorders were randomly selected. Angle's classification, lateral guidance pattern, range of maximal mouth opening, preferred chewing side, and affected side were investigated clinically. Mandibular torque rotational movement during opening was recorded with $BioEGN^{(R)}$ and vibration of temporomandibular joint during opening was recorded with $Sonopak^{(R)}$. After clinical diagnosis was made, visual analogue scale(VAS) was used for evaluation of clinical progress of the subject's chief complaints. The author calculated VAS treatment index(VAS Ti) from the record of VAS. The more VAS Ti was, the less remission of subjective symptom was, The data were analyzed with SAS/Stat program and the results of this study were as follows: 1. There were no significant difference in all the variables of joint vibration by age and sex. 2. Integral and peak amplitude in patients of Angle's class I were higher than those of class II or III patients. Integral in patients of group function was higher than that in patients of canine guidance or other types of lateral excursion. 3. As to Angle's classification or lateral guidance type, there were almost not significant difference between subgroup of same class or type and subgroup of different class or type on both sides. And there were also almost not difference between one side and the other side related to preferred chewing side or affected side. 4. Patients with disk displacement with reduction showed higher value of integral and peak amplitude than any other patients. 5. Joint vibration variables significantly correlated with VAS Ti of pain. with clinical range of mouth opening, and with ingredients of mandibular torque rotational movement.

• 한국전자파학회논문지
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• 제15권4호
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• pp.414-420
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• 2004

Orthogonal frequency-division multiplexing(OFDM)은 무선 환경에서 고속 데이터 전송에 적합한 방식이다. 그러나 높은 peak-to-average power ratio(PAPR)로 인하여 비선형 왜곡의 문제점이 있다. 여러 PAPR 저감 방법 중에서 partial transmit sequences(PTS)는 매우 유연하고 스펙트럼 왜곡이 발생하지 않는 좋은 방법으로 평가된다. 이 방법의 문제점은 최적화된 rotation factor에 대한 부가 정보를 수신기에 전송해야만 데이터를 정확히 복원할 수 있다는 점이다. 본 논문에서는 기존 PTS 방식에서 기준 심볼을 이용하여 부가 정보를 전송하는 기법을 새롭게 제안한다. 이 기법은 rotation factors의 정보를 기준 심볼의 위상으로 표현하는 방법이다. 시뮬레이션 결과를 통해 제안 방식이 종전의 PTS와 동일한 PAPR 저감 성능을 가지면서 정확하게 데이터를 복원하여 요구 BER이 만족됨을 확인하였다. 또한, 제안 방식은 변조 방식에 무관하며, 간단하게 시스템을 구현할 수 있다.

• 한국통신학회논문지
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• 제34권1C호
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• pp.131-137
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• 2009

Bin offset carrier (BOC) 신호 동기화 과정은 GPS, Galileo와 같은 위성항법시스템에서 가장 중요한 단계이다. BOC 신호 동기화 과정은 일반적으로, 수신 BOC 신호와 단말기의 BOC 신호 사이의 상관함수를 이용하여 이루서진다. 따라서 BOC 자기상관함수의 다중 첨두 문제는 동기화 오차의 주요한 원인이 된다. 최근 Julien에 의해 BOC 상관함수 상의 주변 첨두 크기를 줄일 수 있는 기법이 제안되었다. 그러나 이 기법은 주변 첨두를 완벽히 제거하지 못하며, 적용할 수 있는 신호도 제한적이다. 본 논문에서는 주변 첨두가 완벽히 제거된 새로운 상관함수를 제안하였다. 제안한 상관함수는 sine 위상 및 cosine 위상의 BOC 신호 모두에 적용할 수 있으며, 주변 첨두를 완벽히 제거할 수 있다. 또한 제안한 상관함수를 효율적으로 구현할 수 있는 상관기 구조도 제안하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 D
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• pp.2668-2670
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• 2004

This paper presents an advanced load control method in Direct Load Control(DLC) system. It is important to aggregate a various demand side resource which is surely controllable at the peak power time for a successful DLC system. Because the DLC system use simple On/Off control that may cause a harmful effect on a plant to reduce a peak power load, there are some restriction on deriving a voluntary participation of demand side resource. So it needs a new approach to direct load control method, and this paper describes an advanced load control method using control logic which is based on load properties. This method is easy to take account of a various characteristic of load, it can be use as a dynamic control logic which is good for adaptive control. The suggested control logic method is verified by modeling a control logic for a turbo refrigerator which affects on peak power in summer season.

• The Journal of Korean Physical Therapy
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• 제11권1호
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• pp.111-119
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• 1999

The object of study who healthufl thirty persons have been enforced Isokinetic exercise of non-dominant muscular strength. The next same that each dominant muscular strength and non-dominant strength, peak torque and total work have been comparative analysis 1, Shoulder muscles comparion increase peak torque at low speed from pretraining Isokinetic exercise of non-dominant strength side to ten week of post-training.. Flexor and extensor come out high and statistically significant 6, 8, 10 week than pretraining. Adductor and abductor come out high and statistically significant 4, 6, 8. 10 week then pre-training, Internal rotator and external rotator come out statistically significant 2, 4, 6, 8, 10 week then pre-ttraining. 2. Shoulder muscles comparion increase peak torque at high speed from pre-training Isokinetic execise of non-dominant strenght side to ten week of post-training. Flexor and extensor come out high and statistically significant 4, 6, 8, 10 week then pie-training. Adductor and abductor come out high and statistically significant 2, 4, 6, 8, 10 week than pre-training. Futernal rotator and external rotator come out statistically significant 4. 6, 8, 10 week than pre-training.

• 한국통신학회논문지
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• 제31권2A호
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• pp.187-193
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• 2006

Multicarrier systems has major shortcomings due to the large numbers of subcarrier. One of the shortcomings is the high peak-to-average power ratio(PAPR), which causes nonlinearity distortion in the transmitter, and degrades the performance of the system significantly. Partial transmit sequence(PTS) is one of the best approaches that can significantly improve the statistics of the PAPR of an orthogonal frequency division multiplexing(OFDM) signal. Guided scrambling(GS) is an extension of self-synchronizing scrambling. It is also capable of guiding the scrambling process to produce a balanced encoded bit stream. In this paper, we propose a sub-optimal algorithm to optimize the phase factor in PTS. In addition, we integrate GS coding with this method. The proposed Hybrid algorithm can get much more PAPR reduction at the expense of incur a few error extension and do not require transmission of side information.

• ETRI Journal
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• 제30권4호
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• pp.612-614
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• 2008

A novel linear switched termination active cross-coupled low-voltage differential signaling (LVDS) transceiver operating at 1.5 GHz clock frequency is presented. On the transmitter side, an active cross-coupled linear output driver and a switched termination scheme are applied to achieve high speed with low current. On the receiver side, a shared pre-amplifier scheme is employed to reduce power consumption. The proposed LVDS transceiver implemented in an 80 nm CMOS process is successfully demonstrated to provide a data rate of 6 Gbps/pin, an output data window of 147 ps peak-to-peak, and a data swing of 196 mV. The power consumption is measured to be 4.2 mW/pin at 1.2 V.