• Title/Summary/Keyword: enhancing stability

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Factors Impacting Tourism Demand: An Analysis of 10 ASEAN Countries

  • NGUYEN, Lien Phuong;NGUYEN, Ha Thu
    • The Journal of Asian Finance, Economics and Business
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    • v.8 no.1
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    • pp.385-393
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    • 2021
  • This study investigates the effect of infrastructure, economic sectors and its status, foreign direct investment and private investment, as well as the role of political stability in enhancing the tourism demand in the ASEAN region. The research collected the secondary data from the World Bank database and the UNWTO website of 10 ASEAN countries over 17 years from 2000 to 2016. Applying the generalized method of moments, this research found that, "private investment", "economic sectors", "exchange rate and infrastructure measured by "using of the internet" can increase the tourism demand of a country in the ASEAN region. This research provided evidence indicating that the "foreign direct investment" and "inflation" are two detrimental factors for tourist attraction. The major finding confirmed the positive role of "political stability" in increasing tourist arrivals. First, attracting tourists to a country always poses many challenges to its government. It has been observed in the past decades that though there were many documents, which confirmed that industry can help in promoting tourism, very few studies investigated the role of both agriculture and manufacturing sectors in tourism promotion. Secondly, there are only a few studies which verifies the stability of the political system to the tourism demand in the ASEAN region and that this variable (political stability) has the strongest impact.

Enhancing the Stability of Slopes Located below Roads, Based on the Case of Collapse at the Buk-sil Site, Jeongseon Area, Gangwon Province (강원도 정선지역 북실지구 깎기비탈면 붕괴 사례를 통한 도로 하부 비탈면 안정성 확보에 관한 고찰)

  • Kim, Hong-Gyun;Bae, Sang-Woo;Kim, Seung-Hyun;Koo, Ho-Bon
    • The Journal of Engineering Geology
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    • v.22 no.1
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    • pp.83-94
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    • 2012
  • Slopes are commonly formed both above and below roads located in mountainous terrain and along riversides. The Buk-sil site, a cut slope formed below the road, collapsed in October, 2010. A field investigation determined the causes of failure as improper drainage of valley water from the slope above the road and direct seepage of road-surface water. These factors may have accelerated the collapse via complex interaction between water and sub-surface structures such as bedding. Projection analysis of the site showed the possible involvement of plane, wedge, and toppling failure. Safety factors calculated by Limit Equilibrium Analysis for plane and wedge failure were below the standard for wet conditions. The wetness index, analyzed using topographic factors of the study area, was 9.0-10.5, which is high compared with the values calculated for nearby areas. This finding indicates a high concentration of water flow. We consider that water-flow control on the upper road is crucial for enhancing slope stability at the Buk-sil site.

A Study on Location of STATCOM for Improvement of Total Transfer Capability and Analysis of Total Transfer Capability Considering Transient Stability (전체송전용량 향상을 위한 STATCOM 설비의 적용 위치 선정 및 과도안정도를 고려한 전체송전용량 분석)

  • Lee, Byung-Ha;Baek, Jung-Myoung
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.24 no.4
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    • pp.17-24
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    • 2010
  • The power transfer capability has been recently highlighted as a key issue in many utilities with the power system more stressed and heavy loaded. The total transfer capability in the KEPCO power system is determined mainly by the voltage stability limit and many approaches for enhancement of the total transfer capability has been consistently performed. In this paper, a new transfer capability index to locate the STATCOM(Static Synchronous Compensator) effectively for enhancing the total transfer capability from a static voltage stability viewpoint is presented and it is applied to a small scale power system of IEEE 39-bus test system in order to show the effects of this index. In addition, the effect of transient stability as well as voltage stability to the total transfer capability when loads are increased is analyzed using this small scale power system.

Transient Stability Enhancement of Power System Connected to a Wind Farm Using STATCOM (STATCOM을 이용한 풍력단지가 연계된 전력계통의 과도안정도 향상)

  • Seo, Gyu-Seok;Park, Ji-Ho
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.6
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    • pp.4115-4120
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    • 2015
  • To ensure the transient stability of power system connected to a wind farm, wind power plant must be able to supply reactive power at the point of the common coupling(PCC). The reactive power capability of each individual wind turbine may not sufficient to maintain stability. Also, there are large reactive power losses in connection cables between wind farm and PCC. The static synchronous compensator(STATCOM) is considered for transient stability enhancement, because it provides many advantages such as the fast response time and superior reactive power support capability. In this paper, the effectiveness of a STATCOM in enhancing transient stability of power system connected to a wind farm is presented. The results of dynamic simulations show that STATCOM installed at the PCC can enhance transient stability.

Stability Characteristics of Supercritical High-Pressure Turbines Depending on the Designs of Tilting Pad Journal Bearings

  • Lee, An Sung;Jang, Sun-Yong
    • Tribology and Lubricants
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    • v.37 no.3
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    • pp.99-105
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    • 2021
  • In this study, for a high-pressure turbine (HPT) of 800 MW class supercritical thermal-power plant, considering aerodynamic cross-coupling, we performed a rotordynamic logarithmic decrement (LogDec) stability analysis with various tilting pad journal bearing (TPJB) designs, which several steam turbine OEMs (original equipment manufacturers) currently apply in their supercritical and ultra-supercritical HPTs. We considered the following TPJB designs: 6-Pad load on pad (LOP)/load between pad (LBP), 5-Pad LOP/LBP, Hybrid 3-Pad LOP (lower 3-Pad tilting and upper 1-Pad fixed), and 5-Pad LBPs with the design variables of offset and preload. We used the API Level-I method for a LogDec stability analysis. Following results are summarized only in a standpoint of LogDec stability. The Hybrid 3-Pad LOP TPJBs most excellently outperform all the other TPJBs over nearly a full range of cross-coupled stiffness. In a high range of cross-coupled stiffness, both the 6-Pad LOP and 5-Pad LOP TPJBs may be recommended as a practical conservative bearing design approach for enhancing a rotordynamic stability of the HPT. As expected, in a high range of cross-coupled stiffness, the 6-Pad LBP TPJBs exhibit a better performance than the 5-Pad LBP TPJBs. However, contrary to one's expectation, notably, the 5-Pad LOP TPJBs exhibit a slightly better performance than the 6-Pad LOP TPJBs. Furthermore, we do not recommend any TPJB design efforts of either increasing a pad offset from 0.5 or a pad preload from 0 for the HPT in a standpoint of stability.

Algae-based antioxidant containing selenium yeast (Economase®) enhanced the growth performance, oxidative stability, and meat quality of broiler chickens

  • Nambapana, Maleeka N.;Wickramasuriya, Samiru S.;Macelline, Shemil Priyan;Samarasinghe, K.;Vidanarachchi, Janak K.
    • Animal Bioscience
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    • v.35 no.4
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    • pp.567-576
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    • 2022
  • Objective: An experiment was conducted to determine the effect of algae-based antioxidant containing Se yeast (EconomasE®) on the growth performance, visceral organ weight, meat quality, and oxidative stability of broiler chickens. Methods: Nine hundred sixty, day-old male broiler chickens (Cobb, 43.97±0.55 g) were divided into three dietary treatments and allocated into 12 deep litter pens in a completely randomized design giving 4 replicate cages for each treatment. Three dietary treatments were: i) control (CON, basal diet with sufficient nutrient), ii) vitamin E (VitE, basal diet supplemented with 100 IU VitE), and iii) Algae-based antioxidant containing Se yeast (EcoE, basal diet supplemented with 0.2% algae-based antioxidant containing Se yeast: EconomasE®). Maize soybean meal based basal diets were formulated to meet or exceed the nutrition requirement for broiler chickens. Chickens were fed ad-libitum experimental diets during the 42 days experiment period. On days 21 and 42, body weight and feed intake were measured to calculate the feed conversion ratio of the chickens. Intestine and visceral organs were measured together with meat quality and oxidative stability on days 14 and 42. Results: Chickens fed with EcoE showed improved (p<0.05) growth performance, meat quality, and higher (p<0.05) oxidative stability compared to the chicken fed on CON. Moreover, broiler chickens fed with EcoE showed similar (p<0.05) growth performance with better (p<0.05) meat quality and higher oxidative stability compared to the broiler chickens fed VitE (p<0.05). Conclusion: The algae-based antioxidant containing Se yeast can be supplemented into commercial broiler diets as a substitution of VitE while maintaining growth performance with enhancing meat quality and oxidative stability of the broiler chickens.

Application of the Categorical Data Model for Enhanching the Reliability of the Raters' Ratings and Score Adjustment of the Essay Type Test (논문형 고사 평가에서 평가치 조정과 평가원의 신뢰도 향상에 유효한 CDM 모형의 응용)

  • 홍석강
    • The Mathematical Education
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    • v.38 no.2
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    • pp.165-172
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    • 1999
  • $\sub$e/$\^$2/, that were results from those three sources of such imperfection. Especially to eliminate the differences in severity among many raters the randomization procedure of raters sample was very effective in enhancing the reliability of ratings with comparatively small groups of examinees and raters. And we also introduced the new rating methods, i.e. the 2-step diagnostic procedures to check the sizes of the reliability stability of raters and the sore adjustment method to enumerate the optimal mean values in rating the examinees.

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Charge Confinement and Interfacial Engineering of Electrophosphorescent OLED

  • Chin, Byung-Doo;Lee, Chang-Hee
    • 한국정보디스플레이학회:학술대회논문집
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    • 2007.08b
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    • pp.1203-1205
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    • 2007
  • Confinement of charge carrier and exciton is the essential factor for enhancing the efficiency and stability of the electrophosphorescent devices. The interplay between the properties of emitters and other adjacent layers are studied based on the physical interpretation with difference of energy level, charge carrier mobility, and corresponding charge-trapping behavior.

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Separation of Organic Liquid Mixtures using Plasma Membrane (플라즈마 멤브레인을 이용한 유기용매 혼합을 분리)

  • 김성오;박복기;김두석;박진교;이덕출
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1999.05a
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    • pp.642-644
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    • 1999
  • We have prepared the plasma-polymerized membrane for pervaporation of organic-liquid mixtures by the plasma polymerization technique. Plasma polymerization techniques were utilized in the development of hydrophilic composite membranes having high hydrogen ion permeability and excellent dimensional stability. To develop an organic liquid permselective Membrane, suppressing membrane swearing as well as enhancing the solubility difference is impotant. the objectives of the present study are to disign a suitable membrane for an organic-mixture system by the control of the plasma-polymer solubility.

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Trends and Future Prospects for Transborder Regional Cooperation in Northeast Aisa (뉴스초점: 동북아 초국경적 지역협력의 동향 및 전망)

  • Lee, Sun
    • Journal of the Korean Professional Engineers Association
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    • v.43 no.5
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    • pp.25-30
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    • 2010
  • The 2010 PCRD(Presidential Committee on Regional Development) International Conference aims at designing regional policies to enhance regional growth potential and inter-regional cooperation. Increasing economic interdependence in Northeast Asia in particular among the 3 countries of China, japan and Korea, requires enlightened territorial development policies of each country to accommodate the need for close cooperation and networking across the border. The security problem in the Korean peninsula requires the importance for earnest dialogue and discussion between neighbors about the common future of Northeast Asia. Cross-border cooperation and networking will contribute to enhancing regional stability and development in this era of borderless globalization.

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