• Title/Summary/Keyword: DAMP

Search Result 357, Processing Time 0.023 seconds

A Study on the Optimal Parameter Selection of a Power System Stabilizer for HVDC Linked System (HVDC 연계 시스템의 전력계통 안정화 장치의 적정 파라메터 선정에 관한 연구)

  • 김경철;최홍규;최병숙;강태은;고영곤
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
    • /
    • v.15 no.5
    • /
    • pp.81-89
    • /
    • 2001
  • Power system stabilizer act efficiently to damp the electromechanical oscillations in interconnected power systems. This paper presents an algorithm for the optimal parameter selection of a power system stabilizer in two-area power systems with a series HVDC link. This method is one of the classical techniques by allocating properly pole-zero positions to fit as closely as desired the ideal phase lead between the voltage reference and the generator electrical power and by changing the gain to produce a necessary damping torque over the matched frequency range. The small signal stability and transient stability studies using the PSS parameters obtained from this method show that a natural oscillation frequency of the study case system is adequately damped. The simulation used in the paper was performed by the Power System Toolbox software program based on MATLAB.

  • PDF

Application of TVD-McCormack Scheme to Analysis of Dam-Break Problems (댐붕괴 문제의 해석에 관한 TVD-McCormack기법의 적용)

  • Lee, Jong-Kyu;Kim, Tae-Kwan
    • Journal of Korea Water Resources Association
    • /
    • v.36 no.3 s.134
    • /
    • pp.365-374
    • /
    • 2003
  • This is a study on application of a TVD-Mccormack scheme for the computation of one-dimensional dam-break flows. The TVD scheme not only has the ability to damp out oscillations, but also does not contain terms with adjustable parameters. Moreover, the TVD-McCormack scheme does not cause any additional difficulty when dealing with the source term of the equation and retains second-order accuracy in both space and time. In this study, by appropriately designing the limiter functions, the TVD property can be achieved, and numerical oscillations near a jump discontinuities can be eliminated or reduced. Also, this numerical scheme has less computational errors when the direction of the predictor-corrector step is in the same direction as the shock wane propagation.

Review on Insamyangwi-tang in Hyungsang Medicine (인삼양위탕에 대한 형상의학적 고찰)

  • Kang Kyung Hwa;Lee Yong Tae
    • Journal of Physiology & Pathology in Korean Medicine
    • /
    • v.18 no.6
    • /
    • pp.1569-1574
    • /
    • 2004
  • A general review is made on Insamyangwi-tang(인삼양위탕). Following conclusions are drawn from the clinical cases of Insamyangwi-tang in Hyungsang medicine. Insamyangwi-tang is composed of four different prescriptions of Huisaeng-san, Sakoonja-tang, Eajin-tang and Pyungwi-san. Huisaeng-tang is usually prescribed for the intestinal convulsion. Sakoonja-tang for the deficiency of Ki. Eajintang for retention of phlegm, Insamyangwi-tang is effective in strengthening the spleen, drying the dampness, warming the middle-warmer to stop vomiting, regulating the flow of Ki, and eliminating phlegm. Insamyangwi-tang is applicable to malaria caused by cold, intestinal convulsion, abdominal mass, edema, tympanites, Yin syndrome of exogenous febrile disease, distension, lack of appetite, stomachache, and diarrhea. Persons with the following characteristic in Hyungsang are more susceptible to Insamyangwi-tang ; Jung type, Hyul type, fish type, Taium meridian type, white fat damp constitution, person with big mouth, and woman rather than man.

The Effect of Youndamsagan-tang on a Case of Septic Knee: A Case Report (용담사간탕을 투여한 화농성 슬관절염 환자의 치검 1례)

  • Kang Dae Hee;Kim Young Dal;Kim Chang Nyun;Min Ji Yeun
    • Journal of Physiology & Pathology in Korean Medicine
    • /
    • v.17 no.6
    • /
    • pp.1547-1551
    • /
    • 2003
  • This study was carried out to characterized the effect of Youndamsagan-tang on a Case of Septic Knee. After we gave Youndamsagan-tang to a patient of septic knee, we examined not only symptom of patient but also the thickness and circumference of knee, the change of WBC, ESR, body temperature, VAS. As admission time passes, the pain, flare, swelling and movement of left-side knee joint were improved. The thickness and circumference of knee joint were decreased, and the count of WBC, ESR were decreased. And patient's pain by VAS was subsided. From the above result, administration of Youndamsagan-tang reduces the progressing of pain, flare, swelling and movement in knee joint.

Quantitative Determination of Diarylheptanoid Compounds from Korean Alnus (국내산 오리나무속 식물로부터 Diarylheptanoid계열 화합물의 함량분석)

  • Lim, Hyun-Woo;Kim, Min-Kee;Kim, Hyun-Jung;Shim, Jae-Geul;Kim, Gwang-Ho;Choi, Hyung-Kyoon;Lee, Min-Won
    • Korean Journal of Pharmacognosy
    • /
    • v.35 no.4 s.139
    • /
    • pp.384-387
    • /
    • 2004
  • Genus Alnus are deciduous board-leaved trees or shrubs found in the damp place and mountain and more than 17 species are growing in Korea. The bark of Alnus japonica has been used for the treatment of fever, hemorrhage and diarrehea in oriental traditional medicine. Quantitative analysis of diarylheptanoids which were characteristic components of Alnus species (A. japonica, A. hirsuta, and A. hirsuta var. sibirica), has been conducted by HPLC. The results showed that these plants were rich source of diarylheptanoids and the amount of oregonin and hirsutanonol which were major diarylheptanoids showed seasonal variation.

A Report on Traditional Chinese Medicine (TCM) Constitution Theory and Chinese Health Administration Center (중의체질의학과 치미병(治未病)센터에 대한 보고)

  • Kim, Sang-Hyuk;Joo, Jong-Cheon;Hwang, Dong-Uk;Lee, Si-Woo
    • Journal of Sasang Constitutional Medicine
    • /
    • v.22 no.3
    • /
    • pp.59-66
    • /
    • 2010
  • 1. Objectives: The objectives of this paper are to report Traditional Chinese Medicine (TCM) Constitution Theory and the present state of Chinese Health Administration Center. 2. Methods: We visited China for "China Technology Survey" in 2009. Our purposes were to research for the study of constitutional medicine in China and to search for the Development Plan of Constitutional Medicine Through the Research of Chinese Constitutional Medicine. This paper is the report of the "China Technology Survey". 3. Results & Conclusions: In China, the concept and diagnosis of TCM constitutions is nine(Balanced Constitution, Qi-deficient Constitution, Yang-deficient Constitution, Yin-deficient Constitution, Phlegm-dampness Constitution, Damp-heat Constitution, Stagnant blood Constitution, Stagnant qi Constitution, Inherited specific Constitution). And Chinese government established the Classification and Diagnosis Standards for the Constitutions of TCM in 2009. TCM Constitution Theory is being widely applied at Health Administration Center that treats 'predisease' patients. Theses Chinese clinical implications of constitutional medicine are a good example for "Sasang Constituional Medicine" Care Service.

A Case Report of Skin Scale Treated with Hyulbuchukeotang (어혈(瘀血)로 변증된 피부갑착(皮膚甲錯) 환자에 혈부축어탕(血府逐瘀湯)을 사용한 치험1례 보고)

  • Yoon, Hyeon-Duck;Shin, Oh-Chul;Park, Chi-Sang;Lee, So-Yeon
    • The Journal of Internal Korean Medicine
    • /
    • v.26 no.3
    • /
    • pp.720-724
    • /
    • 2005
  • Objective : Skin scale(皮膚甲錯) refers to an excessive dryness of skin which can be found under such conditions as blood deficiency(血虛), blood heat(血熱), damp heat(濕熱), the weakness of stomach(脾胃虛) and blood stasis(瘀血). Method : A sensitive and nervous patient showed symptoms of insomnia and chest discomfort as well as skin scale. He had great anxiety over his illness. He, therefore, was diagnosed as blood stasis caused by outburst of emotions and was prescribed Hyulbuchukeotang(血府逐瘀湯) to remove blood stasis in chest. Result and Conclusion : After taking Hyulbuchukeotang, insomnia, chest discomfort and skin scale eased off. Since not only blood stasis but also other factors may cause skin scale, more research on such cases must be done to determine the efficacy of Hyulbuchukeotang for skin scale.

  • PDF

Effects of Geopungjeseub-tang(Gufengchushi-tang) on the Changes of Cerebral Blood Flow in Rats (거풍제습탕이 뇌허혈이 유발된 백서의 뇌혈류 변화에 미치는 영향)

  • Hong, Seok;Jeon, Sang-Yun
    • The Journal of Internal Korean Medicine
    • /
    • v.26 no.3
    • /
    • pp.596-604
    • /
    • 2005
  • Objectives : Geopungjeseub-tang(Gufengchushi-tang) has been used in oriental medicine for many centuries as a therapeutic agent for hemiplegia caused by deficiency of qi(氣虛) and damp phlegm(濕痰). This study was performed to evaluate effects of Geopungjeseub-tang extract(GJT) on hemodynamics[regional cerebral blood flow(rCBF), pial arterial diameter(PAD), mean arterial blood pressure(MABP), heart rate(HR)] in normal rats and in rats with cerebral ischemia by middle cerebral artery(MCA) occlusion. Also, effects of adrenergic ${\beta}-receptor$, cyclooxygenase on response to GJT were evaluated. Methods : Laser-doppler flowmetry(LDF) measured changes of rCBF, MABP and HR. Video microscope and width analyzer measured changes in PAD. Results : rCBF and PAD increased after treatment with GJT(10mg/kg, i.v.) during the period of cerebral reperfusion, and pretreatment with indomethacin raised rCBF and PAD increased after treatment with GJT during the same period as above. Pretreatment with propranolol decreased rCBF, but increased after GJT treatment, but raised PAD increased after GJT treatment during this period of reperfusion. Conclusion : CR caused diverse responses were observed in rCBF and PAD after treatment with GJT. ACF action is mediated by adrenergic ${\beta}-receptor$ and cyclooxygenase. Result suggest that GJT has an anti-ischemic effect through the improvement of cerebral hemodynamics and has theraputic potential for cerebral apoplexy.

  • PDF

Detrended canonical correspondence analysis and polar ordination analysis on the forest communities of mudungsan. (DCCA 와 Polar Ordination 에 依한 無等山의 森林 群落 分析)

  • Kim, Chang-Hwan;Kil, Bong-Seop
    • The Korean Journal of Ecology
    • /
    • v.15 no.2
    • /
    • pp.117-125
    • /
    • 1992
  • TWINSPAN(two-way indicator species analysis), DCCA(detrended canonical correspondence analysis) and polar ordination method wee used so as to analyze the the relation between forest vegetation and hibitat of mudungsan(1, 187m) located in kwangju area. Vegetationsurvey consulted 1:25, 000 topographical map, set up 41 quadrats and analyzed from April, 1990 to August, 1991. Forest vegetation of mudungsan was classifild to quercus acutissima community, fraxinus mandshurica community, quercus mongolica community, quercus serrata community, quercus dentata community, quercus variabilis community, and pinus densiflora community by TWINSPANmethod, and this almost coincide with the result of plar ordination. according to DCCA analysis, P. densiflora community was formed in xeric and low altitude region which soil nutrient was poor, compared with other communities. q. variabilis and q. acutissima community wee distributed in the region that low altitude and organic matter content was comparatively low, but q. acutissima community was formed in a damp region while q. variabilis community in a xeric region. q. mongolica and f. mandshurica formed the communities in a high altitude region, especially f. mandshurica cmmunity was distributed in a high humidity region. According to polar ordination analysis, the forest vegetation was classified to 7 communities by means of environmental gradient such as humidity, organic matter, ph, temperature, c.e.c and P2O5.

  • PDF

A Study on the Optimal Parameter Selection of a Power System Stabilizer and Power Converters for HVDC Linked System (HVDC 연계 시스템의 전력계통 안정화 장치와 전력변환기 적정 파라미터 선정에 관한 연구)

  • 조의상;김경철;최홍규
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
    • /
    • 2001.11a
    • /
    • pp.65-72
    • /
    • 2001
  • Power system stabilizer act efficiently to damp the electromechanical oscillations in interconnected power systems. This paper presents an algorithm for the optimal parameter selection of a power system stabilizer in two-area power systems with a series HVDC link. This method is one of the classical techniques by allocating properly pole-zero positions to fit as closely as desired the ideal phase lead between the voltage reference and the generator electrical power and by changing the gain to produce a necessary damping torque over the matched frequency range. Control of HVDC converter and inverter are used a constant current loop. Proper parameters of PI controllers are obtain based on the Root-locus technique in other to have sufficient speed and stability margin to cope with charging reference values and disturbance. The small signal stability arid transient stability studies using the PSS parameters obtained from this method show that a natural oscillation frequency of the studycase system is adequately damped. Also the simulation results using the HVDC converter and inverter parameters obtained from this proposed method show proper current control characteristics. The simulation used in the paper was performed by the Power System Toolbox software program based on MATLAB.

  • PDF