• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.7
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• pp.800-808
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• 2004

Wind tunnel test of an airplane model with forward swept wing was done in KARI LSWT to evaluate and measure the aerodynamic characteristics of initially designed configuration. Since the given wing planform did not fully satisfy the design requirements, local flow control devices such as vortilon, vortex generator and flow fence were used to delay separation and to enhance aerodynamic characteristics. Also decision making processes of design parameters such as vertical tail boom length, the location, size and the incidence angle of horizontal tail were discussed. The general aerodynamic characteristics of forward swept wing for various control surface deflection conditions of flap, aileron and elevator were also given.

• Archives of Pharmacal Research
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• v.22 no.6
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• pp.554-558
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• 1999

The effects of ethanolic extract (EEP) of propolis on chronic inflammation were evaluated using rat adjuvant arthritis. In the chronic inflammatory animal model, the arthritis index was suppressed by EEP treatments (50 mg/kg/day and 100 gm/kg/day, p.o.). Moreover, physical weakness, induced by the chronic disease state, was dose-dependently improved in the EEP-treated groups. It s analgesic effect, assessed using the tail-flick test, was comparable to prednisolone (2.5 mg/kg/day, p.o.) and acetyl salicylic acid (100 mg/kg/day, p.o.). In carrageenan rat hind paw edema, which was conducted to test the effects of subfractions of EEP, the petroleum ether sub-fraction (100 mg/kg, p.o.) showed an inhibitor effect on the paw edema whereas EEP (200 mg/kg, p.o.) showed a significant anti-inflammatory effect at 3 and 4 hrs after carrageenan injection. From these results, we conclude that the ethanolic extract of propolis had a profound anti-inflammatory effects on both chronic and acute inflammations.

• Journal of Acupuncture Research
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• v.19 no.5
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• pp.176-188
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• 2002

Objective : Sono-acupoint (SA) therapy is a new therapeutic technique that combined with acupuncture points, herbal medicine and ultrasound therapy. This study was carried out to investigate the analgesic and anti-inflammatory effects of sono-acupoint therapy. Methods : We performed the tail-flick test with normal rats to examine the tail-flick latency (TFL), and the Freund's adjuvant-induced arthritis rat model to examine the edema, skin temperature and serum concentration of c-reactive protein and rheumatoid factor (RF). Herbal SA (HSA) treatment was performed at bilateral Zusanli (ST36) with the hanbang-gel made of several selected herbal drugs in Sprague-Dawley rats (male, $250{\pm}30g$). General SA (GSA) treatment was performed at bilateral Zusanli (ST36) with the gel used in ultrasound therapy. In arthritis rat model, Freund's adjuvant (50mg/ml) was injected in dorsal part of right foot, and these treatments were performed after 15 days. Results : TFL was lengthened after SA treatments. Skin temperature and RF concentration that were the evidence of arthritis in rats were decreased by HSA treatment (P < 0.05). Conclusion : These results indicate that HSA has the analgesic and anti-inflammatory effects in rats, and further developments will produce the advance of this new therapeutic skill.

• Journal of Ocean Engineering and Technology
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• v.19 no.6 s.67
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• pp.58-63
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• 2005

The estimation of springing responses for recent ships is carried out, and application to a ship design is described. To this aim, springing effects on hull girder were re-evaluated, including non-linear wave excitations and torsional vibrations of the hull. The Timoshenko beam model was used to calculate stress distribution on the hull girder, using the superposition method. The quadratic strip method was employed to calculate the hydrodynamic forces and moments on the hull. In order to remove the irregular frequencies, we adopted 'rigid lid' on the hull free surface level, and addedasymptotic interpolation along the high frequency range. Several applications were carried out on the following existing ships: The Bishop and Price's container ship, S-175 container ship, large container, VLCC, and ore carrier. One of them is compared with the ship measurement result, while another with that of the model test. The comparison between the analytical solution and the numerical solution for a homogeneous beam-type artificial ship shows good agreement. It is found that Most springing energy comesfrom high frequency waves for the ships having low natural frequency and North Atlantic route etc. Therefore, the high frequency tail of the wave spectrum should be increased by $\omega$$\^{-3}$ instead of $\omega$$\^{-4}$ or $\omega$$\^{-5}$ for the springing calculation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.6
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• pp.1610-1618
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• 1998

In this paper, we present the FB(Fair Buffering) mechanism for the efficient support of TCP traffic over UBR connections in the subnet ATM model. We show that both throughput and fairness may be improved with the FB mechanism. The FB mechanism is founded on the observation that the performance of TCP over UBR connections is optimal when the buffer space is allocated in proportion to the connection's bandwidth-delay product. We compare through simulation the performance of the existing drop-tail, EB(Equal Buffering) and the proposed FB buffer management schemes, with and without RR(Roung-Robin) scheduling, and demonstrate that the proposed FB mechanism is most effective when used in conjunction with the RR scheduling scheme.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2004.11a
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• pp.173-178
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• 2004

The estimation of springing responses for recent ships are carried out and application to a ship design are described. To this aim, springing effects on hull girder were re-evaluated including non-linear wave excitations and torsional vibrations of the hull. The Timoshenko beam model was used to calculate stress distribution on the hull girder by the superposition method. The strip method was employed to calculate the hydrodynamic forces and moments on the hull. In order to remove the irregular frequencies, we adopted 'rigid lid' on the hull free surface level and added asymptotic interpolation along the high frequency range. Several applications to the existing ships were carried out. They are Bishop and Price's container ship, S-175 container ship, large container, VLCC and ore carrier. One of them is compared with ship measurement result while another with that of model test. Comparison between analytical solution and numerical one for homogeneous beam type artificial ship shows good agreement. It is found that most springing energy came from high frequency waves for the ships having low natural frequency and North Atlantic route etc. Therefore, the high frequency tail of the wave spectrum should be increased by $\omega^{-3}\;instead\;of\;\omega^{-4}\;or\;\omega^{-5}$ for springing calculation.

• Journal of Acupuncture Research
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• v.20 no.2
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• pp.85-97
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• 2003

Introduction : In this study, the analgesic effect and its mechanism of bee venom aqua-acupuncture on complete Freund's adjuvant-induced arthritis in rats was investigated. It has been reported from a neurochemical standpoint that bee venom exerts antinociceptive effects on inflammation and that the opioid system and adrenergic system play important roles in acupuncture analgesia. however, it is not known whether central opioid and ${\alpha}2$-adrenergic components of the intrinsic descending analgesic system are activated after bee venom aqua-acupuncture. Methods : Bee venom(1mg/kg) was subcutaneously aqua-acupunctured into Joksamni($ST_{36}$) of rats with complete Freund's adjuvant(CFA)- induced arthritis and was checked of increase in TFL. Opioid and ${\alpha}_2$-adrenergic neurotransmitter system were examined by naloxone as an opioid receptor antagonist, and yohimbine as ${\alpha}_2$-adrenoceptor antagonist prior to bee venom aqua-acupuncture. Results : The following results have been obtained. 1. The tail flick latency in the rat model with adjuvant-induced arthritis was significantly decreased in 2 weeks. 2. The tail flick latency in the rat model with adjuvant-induced arthritis was increased in bee venom aqua-acupuncture group compared to the normal saline aqua-acupuncture group. 3. Analgesic effect of bee venom was antagonized by yohimbine not by naloxone pretreatment in the rat model adjuvant-induced arthritis. Conclusions : Bee venom aqua-acupuncture has an analgesic effect on the rat model of adjuvant-induced of adjuvant-induced arthritis and has antinociception mediated by ${\alpha}_2$-adrenergic system.

• Journal of Acupuncture Research
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• v.20 no.3
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• pp.117-130
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• 2003

To study the analgesic and effect and its mechanism of eletroacupunture(EA) on the chronic inflammatory pain 50 rats were induced with arthralgesia by injecting complete freund's adjuvant(CFA). Two weeks after the injection of CFA, EA stimulation(2Hz, 0.07mA, 0.3ms) was delivered to Jogsamni($ST_{36}$) for 20 minutes. Analgesic effect was evaluated by using the tail flick latency(TFL) and the analgesic mechanism was observed by applying TFL with the pretreatment with naloxone and yohimbine. The results were as follows ; 1. TFL level for the model of adjuvant-induced arthritis decreased as time went by and it induced the hyperalgesia. 2. EA stimulation delivered to Jogsamni($ST_{36}$) for 20 minutes in the rat model of adjuvant-induced arthritis brought analgesic effect and its effect had lasted for 40 minutes after the stimulation. 3. The analgesic effect of Jogsamni($ST_{36}$) EA in the rat model of adjuvant-induced arthritis was blocked by pretreatment with naloxone(2mg/kg,i.p). This result suggests that the EA effect on the chronic inflammatory pain can be related to the endogenous opioid mechanism. 4. The analgesic effect of Jogsamni($ST_{36}$) EA in the rat model of adjuvant-induced arthritis was blocked by pretreatment with naloxone(2mg/kg,i.p). This result suggests that the EA effect on the chronic inflammatory pain can be related to the ${\alpha}_2$-adrenergic mechanism.

• Journal of Acupuncture Research
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• v.28 no.1
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• pp.37-44
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• 2011

배경 및 목적 : 봉독약침요법(bee venom pharmacopuncture, BVP)은 rheumatoid arthritis(RA)의 치료에 활용되고 있으나, RA로 인한 염증성 통증에 대한 봉독약침의 진통효과와 specific mechanism은 아직까지 명확하게 밝혀지지 않았다. 이에 본 연구에서는 RA animal model로서 collagen-induced arthritis(CIA) rat model에서 봉독약침의 a1-adrenergic, 5HT-3 그리고 muscarinic cholinergic mechanism을 확인하고자 한다. 방법 : CIA를 유도하기 위하여 male Sprague-Dawley rat에 freund's incomplete adjuvant에 유화(乳化)시킨 bovine type II collagen을 주입하고 14일 후 booster injection 시행하였다. 진통효과는 tail flick latency (TFL)로 평가하였다. 결과 : 관절염의 유도 이후 염증성 통증 역치는 시간이 지나면서 낮아지며, 5주 이후로는 통증 역치에 큰 변화가 없이 유지되었다. 첫 번째 immunization으로부터 5주 경과 후 족삼리($ST_{36}$)에 봉독약침처치(0.25 mg/ kg)를 시행하여 유의한 진통효과를 관찰하였다. 또한 봉독약침의 진통효과는 ondansetron(5HT-3 receptor antagonist, 0.5mg/kg, i.p.), atropine(muscarinic cholinergic receptor antagonist, 1mg/kg, i.p.)의 전처치에 의하여 억제되었으나, prazosin(a1-adrenergic receptor antagonist, 1mg/kg, i.p.)의 전처치에 의해서는 억제되지 않았다. 결론 : 봉독약침은 CIA로 인한 염증성 통증에 유의한 진통효과를 나타내며 그 analgesic mechanism은 5HT-3와 muscarinic cholinergic receptor에 의하여 매개되며 a1-adrenergic receptor에 의하여 매개되지는 않았다.

• International Journal of Aeronautical and Space Sciences
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• v.18 no.2
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• pp.290-299
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• 2017

Reconfigurable flight control using various kinds of adaptive control methods has been studied since the 1970s to enhance the survivability of aircraft in case of severe in-flight failure. Early studies were mainly focused on the failure of actuators. Recently, studies of reconfigurable flight controls that can accommodate complex damage (partial wing and tail loss) in conventional aircraft were reported. However, the partial wing loss effects on the aerodynamics of conventional type aircraft are quite different to those of BWB(blended wing body) aircraft. In this paper, a reconfigurable flight control algorithm was designed using a direct model reference adaptive method to overcome the instability caused by a complex damage of a BWB aircraft. A model reference adaptive control was incorporated into the inner loop rate control system enhancing the performance of the baseline control to cope with abrupt loss of stability. Gains of the model reference adaptive control were polled out using the Liapunov's stability theorem. Outer loop attitude autopilot was designed to manage roll and pitch of the BWB UAV as well. A 6-DOF dynamic model was built-up, where the normal flight can be made to switch to the damaged state abruptly reflecting the possible real flight situation. 22% of right wing loss as well as 25% loss for both vertical tail and rudder control surface were considered in this study. Static aerodynamic coefficients were obtained via wind tunnel test. Numerical simulations were conducted to demonstrate the performance of the reconfigurable flight control system.