• Title/Summary/Keyword: Stability Indices

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Sensitivity Analysis on the Stability of a Submarine Concerning its Design Parameters (잠수함의 설계 인자들에 대해 안정성 지수가 가지는 민감도 해석)

  • Yeo Dong-Jin;Yoon Hyeon-Kyu;Kim Yeon-Gyu;Lee Chang-Min
    • Journal of the Society of Naval Architects of Korea
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    • v.43 no.4 s.148
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    • pp.521-528
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    • 2006
  • In this study, we developed a new systematic approach to assess the influence of geometric parameter change on the horizontal and vertical stability indices. To do this, three phases of sensitivity analyses were carried out. First, typical geometric parameters were defined and their effects on hydrodynamic coefficients were assessed by the Sensitivity Analysis (SA) of the indirect method. Second, the effects of hydrodynamic coefficients on the stability indices were calculated. Finally, the sensitivities of geometric parameters on the stability indices were obtained by merging the outputs of two phases using chain rule. The developed approach cau contribute to a submarine designer to determine geometric parameters satisfying pre-requirements about stability systematically.

An Analysis on the Management Situation of a Hansalim Consumer Cooperatives (A생협에 대한 경영성과 분석)

  • Kim, Ho
    • Korean Journal of Organic Agriculture
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    • v.28 no.1
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    • pp.59-68
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    • 2020
  • This study analyzed and suggested management situations and improving issues on a consumer cooperatives which has supplied environmentally friendly agricultural products from the year 2002. Indices of management analysis are stability ratio, activity ratio and profitability ratio. Management Stability ratio indices are debt ratio, net worth ratio, fixed ratio and current ratio. Management activity ratio ones include fixed assets turnover and net worth turnover. And profitability ratio is showed through return on investment, net return on sales and return on equity. In order to analyze these indices, financial statements after the closing entires are used each year.

Monetary Policy Independence during Reversal Phases of Domestic-Foreign Interest Rate Differentials

  • Kyunghun Kim
    • East Asian Economic Review
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    • v.28 no.2
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    • pp.221-244
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    • 2024
  • This study examines how the independence of monetary policy changes in situations where the interest rate differential between domestic and foreign rates inverts, utilizing the trilemma indices. For analysis, this paper uses the trilemma indices developed by Kim et al. (2017) to analyze the relationship between the monetary policy independence index and the other two trilemma indices, namely the capital account openness index and the exchange rate stability index, across 45 countries from 2002 to 2018. The analysis reveals that the trilemma's validity is contingent. In particular, no statistically significant negative correlation was found between the monetary policy independence index and exchange rate stability index during periods of interest rate differential inversion. A positive correlation emerges between exchange rate stability and the independence of monetary policy, particularly when the inverted interest rate differential exceeds a certain threshold. This situation, where the exchange rate remains stable despite low domestic interest rates, implies that the central bank is effectively managing monetary policy to appropriately respond to economic conditions, which is reflected in the monetary policy independence index.

A Novel Line Stability Index for Voltage Stability Analysis and Contingency Ranking in Power System Using Fuzzy Based Load Flow

  • Kanimozhi, R.;Selvi, K.
    • Journal of Electrical Engineering and Technology
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    • v.8 no.4
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    • pp.694-703
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    • 2013
  • In electric power system, the line stability indices adopted in most of the instances laid stress on variation of reactive power than real power variation of the transmission line. In this paper, a proposal is made with the formulation of a New Voltage Stability Index (NVSI) which originates from the equation of a two bus network, neglecting the resistance of transmission line, resulting in appreciable variations in both real and reactive loading. The efficacy of the index and fuzzy based load flow are validated with IEEE 30 bus and Tamil Nadu Electricity Board (TNEB) 69 bus system, a practical system in India. The results could prove that the identification of weak bus and critical line in both systems is effectively done. The weak area of the practical system and the contingency ranking with overloading either line or generator outages are found by conducting contingency analysis using NVSI.

A Novel Method for Clustering Critical Generator by using Stability Indices and Energy Margin (안정도 지수와 에너지 마진을 이용한 불안정 발전기의 clustering 법)

  • Chang Dong-Hwan;Jung Yun-Jae;Chun Yeonghan;Nam Hae-Kon
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.54 no.9
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    • pp.441-448
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    • 2005
  • On-line dynamic security assessment is becoming more and more important for the stable operation of power systems as load level increases. The necessity is getting apparent under Electricity Market environments, as operation of power system is exposed to more various operating conditions. For on-line dynamic security assessment, fast transient stability analysis tool is required for contingency selection. The TEF(Transient Energy Function) method is a good candidate for this purpose. The clustering of critical generators is crucial for the precise and fast calculation of energy margin. In this paper, we propose a new method for fast decision of mode of instability by using stability indices. Case study shows very promising results.

Characteristics of Atmospheric Stability Index of Airmass thunderstorm day at Busan (부산지역 기단성 뇌우 발생일의 대기안정도지수 특성)

  • Jeon, Byung Il
    • Journal of Wetlands Research
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    • v.5 no.1
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    • pp.29-40
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    • 2003
  • This study was performed to research the relation between airmass thunderstorm and stability index with 12 years meteorological data(1990~2001) at Busan. Also We used the analysed stability indices from University of Wyoming to consider airmass thunderstorm. The frequency of thunderstorm occurrence during 12 years was 156 days(annual mean 13days). The airmass thunderstorm frequency was 14 days, most of those occurrence were summertime(59%). And occurrence hour of airmass thunderstorm was distributed from 1300LST to 2100LST broadly. The highest forecast index for airmass thunderstorm at Busan was K index, the lowest forecast index was SWEAT index. The forecasting of thunderstorms is based primary on the concepts of conditional instability, convective instability, and forced lifting of air near the surface. Instability is a critical factor in severe weather development. Severe weather stability indices can be a useful tool when applied correctly to a given convective weather situation.

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Trends of Stability Indices and Environmental Parameters Derived from the Rawinsonde Data over South Korea

  • Eom, Hyo-Sik;Suh, Myoung-Seok
    • Journal of the Korean earth science society
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    • v.32 no.5
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    • pp.461-473
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    • 2011
  • In this paper, trends of the widely used stability indices (SIs) and environmental parameters (EPs) were examined by using the 30-year routine rawinsonde data observed in three upper air observatories (Osan, Gwangju and Pohang) over South Korea. To take into account of the contribution of water vapor to a parcel density, we applied the virtual temperature correction in calculating the SIs and EPs. The trends of SIs and EPs indicated significant increases of temperature and moisture contents, especially at the low-to-mid troposphere during the last 10 years. The warming trend in the lower troposphere shows about 3 times greater than that of the global average (+0.10- $+0.20^{\circ}C$/10 years), whereas the cooling trend of lower stratosphere demonstrates a similar trend with the global average (-0.33- $-0.60^{\circ}C$/10 years). The vertical stability is clearly reduced due to the unsymmetrical change of atmospheric elements. The unstabilizing trend with the increased moisture contents gradually changed the atmospheric environment in South Korea into the conditions favorable for the occurrence of severe weather or intensifications of such events. These trends are consistent with the recent observations, which showed clear increase in the intensity and frequency of heavy rainfalls.

Finding Stability Indices Using Evolutionary Programming (진화 프로그래밍을 이용한 안정지수 결정)

  • 신진욱;김인택;강환일
    • Proceedings of the Korean Institute of Intelligent Systems Conference
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    • 2000.05a
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    • pp.39-42
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    • 2000
  • Both evolutionary programming (EP) and genetic algorithm (GA) are classified as evolutionary computation. They have been successful in finding a solution in a wide search space. In this paper, our objectives are to find the coefficients of characteristic equation, in terms of the stability indices using EP and GA, and to make a comparison of both methods.

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Development of Performance Indices for Agro-food Distribution Corporations Based on the AHP Method (AHP기법을 이용한 농식품 유통법인 경영진단지표 개발)

  • Kim, Dong-Hwan;Hyun, Jong-Ki
    • Journal of Distribution Science
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    • v.15 no.12
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    • pp.95-102
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    • 2017
  • Purpose - This study aims to develop diagnostic indices for managerial performance of agro-food distribution corporations. In particular, weights of diagnostic indices were estimated using the AHP method. Management diagnosis on agro-food distribution corporations is expected to increase their competitiveness in the domestic market as well as in international markets. Research design, data, and methodology - It develops weights or importance of the diagnostic indices based upon the survey of 21 experts in food distribution management. The survey was carried out using e-mail. Management diagnostic indices were developed based upon four BSC(Balanced Scorecard) perspectives of finance, learning/growth/leadership, customer, and internal process/technology. Results - Diagnostic indices on financial perspective consist on profitability, productivity, growth, stability and activity. Learning and leadership perspective indices consist of management will, CEO leadership, level of learning, innovation, and level of management information system. Customer perspective indices are branding, customer and channel management and internal process/technology indices consist of fourteen sub-indices representing technologies, efficiency, and dynamics. It was estimated that the weight of financial perspective index was 0.3, internal process/technology perspective index 0.248, customer category index 0.247, and learning, growth and leadership perspective index 0.205. This study also estimates weights of sub-indices for managerial diagnosis by four different perspectives. Estimated weight of profitability (0.085) is the greatest among financial perspective indices, followed by stability (0.072), growth (0.053), productivity (0.051), and activity (0.038). While estimated weights of leadership, capability, and information indices are 0.100, 0.061, and 0.044 respectively, weights of marketing, customer management, and quality and service indices are 0.104, 0.093, and 0.051, respectively. Among internal process/technology perspective, estimated weights of efficiency, technology, and innovation indices are 0.106, 0.088, and 0.054, respectively. Conclusions - The diagnostic indices for managerial performance of agro-food distribution corporations would be utilized by agro-food distribution corporations themselves, extension service institutions, and consultants. It is also expected that central and local governments use diagnostic indices developed in this study for the purpose of evaluating the effects of governmental support programs for agro-food distribution corporations. Futhermore researchers and consultants would modify diagnostic indices developed in this study, reflecting characteristics and situation of types of agro-food distribution corporations.

Independence and Transparency of the Central Bank of Kazakhstan

  • Nurbayev, Daniyar
    • The Journal of Asian Finance, Economics and Business
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    • v.2 no.4
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    • pp.31-38
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    • 2015
  • During the last two decades the idea that central bank independence and transparency helps to maintain price stability, became popular among economists and central bankers. Many countries' governments give their monetary authorities higher independence and transparency to achieve the price stability goal. However, emerging countries such as Kazakhstan, suffer from high inflation. This inflation occurs largely due to a low level of independence and transparency of central banks. This research project measures the current level of independence and transparency of central bank of Kazakhstan. Indices were used to measure central bank independence and transparency. Central bank independence was measured by two types of indices: based on central bank laws (legal independence) and based on central banks governor's turnover (TOR). Developing countries have a weak legal framework, implying that a legal independence index cannot be appropriate to use as a measures of actual independence. Therefore, by paying attention to the other two indices, we can say that the central bank of Kazakhstan has a low level of independence and transparency. This, in turn, can be one of the causes of high inflation in Kazakhstan.