• The Journal of Asian Finance, Economics and Business
• /
• 제5권4호
• /
• pp.9-20
• /
• 2018

Global rating agencies, such as Moody's and S&P, have assigned credit ratings to corporate bonds issued by Japanese firms since 1980s. Local Japanese rating agencies, such as R&I and JCR, have more market share than the global raters. We examine the yield spreads of 1,050 yen-denominated corporate bonds issued by financial firms in Japan from 1998 to 2014 and find no evidence that bonds rated by at least one global agency are associated with a significant reduction in the cost of debt as compared to those rated by only local rating agencies. Unlike non-financial firms, the reputation effect of global rating agencies does not exist for Japanese financial firms. We also observe that firms with less information asymmetry are more likely to acquire ratings from Moody's or S&P. Additionally, the firm's financial profile does not affect its choice to seek out ratings from global raters. Our findings are contradictory to those by Han, Pagano, and Shin (2012), who employ bonds issued by non-financial firms in Japan. Our conjecture is that the asymmetric nature of financial firms makes investors less likely to depend on a credit risk assessment by rating agencies in determining the yields of new bonds.

• Journal of Power Electronics
• /
• 제17권2호
• /
• pp.522-532
• /
• 2017

This paper presents a novel integrated structure for a cascaded distribution static compensator (D-STATCOM) and distribution transformer for medium-voltage reactive power compensation. The cascaded multilevel converter is connected to a system via a group of special designed taps on the primary windings of the Dyn11 connection distribution transformer. The three-phase winding taps are symmetrically arranged and the connection point voltage can be decreased to half of the line-to-line voltage at most. Thus, the voltage stress for the D-STATCOM is reduced and a compromise between the voltage rating and the current rating can be achieved. The spare capacity of the distribution transformer can also be fully used. The working mechanism is explained in detail and a modified control strategy is proposed for reactive power compensation. Finally, both simulation and scaled-down prototype experimental results are provided to verify the feasibility and effectiveness of the proposed connection structure and control strategy.

• 전기학회논문지
• /
• 제58권10호
• /
• pp.1835-1841
• /
• 2009

We analyze the problem of recloser-fuse coordination when a superconducting fault current limiter (SFCL) is installed to a power distribution system. Generally, The recloser is installed to upstream of fuse to protect against both permanent fault and temporary one appropriately. However, in a power distribution system with SFCL, the fault current is decreased by the effect of the impedance value of the SFCL and when a permanent fault occurs, the fuse may not melt during the last delay operation of the recloser because of the insufficient heat from the decreased current. Therefore, when SFCLs are applied into a power distribution system, the rating of the fuse has to be reselected to coordinate recloser to fuse effectively. To solve these problems, this paper analysed the operation of recloser-fuse coordination and presented the improved recloser-fuse coordination method in a power distribution system with SFCL using PSCAD/EMTDC.

• Ocean Science Journal
• /
• 제41권3호
• /
• pp.149-161
• /
• 2006

The aims of this study are 1) to construct a database using geostatistics and Geographic Information System (GIS), and 2) to derive the spatial relationships between manganese nodule abundance and other geological factors such as metal grade, slope, water depth, topography, and acoustic characteristics of the sub-bottom. Using GIS, it is possible to analyze a large amount of data efficiently, and to maximize the practical application, to increase specialization, and to enhance the accuracy of the analyses. The greater the copper and nickel grade, the higher the rating. The distribution pattern of nickel grade is similar to that of copper grade. The slopes are generally less than $3^{\circ}$ except for seamounts and cliff areas. The rating shows no correlation with slope. The rating is highest for slopes between 2.5 and $3.5^{\circ}$ in block N1 and between 4.0 and $4.5^{\circ}$ in block N3. The topography is classified into five groups: seamount, hill crest, hill slant, hill base or plain, and seafloor basin or valley. The rating proves lowest for seamount and hill crest. Our results show that the rating increases with the water depth in the study area. Nodule abundance dose not show any significant relationship with the thickness of the upper transparent layer in the study area.

• Smart Structures and Systems
• /
• 제12권6호
• /
• pp.661-678
• /
• 2013

In this paper, a wireless sensing system for structural field evaluation and rating of bridges is presented. The system uses a wireless platform integrated with traditional analogue sensors including strain gages and accelerometers along with the operating software. A wireless vehicle position indicator is developed using a tri-axial accelerometer node that is mounted on the test vehicle, and was used for identifying the moving truck position during load testing. The developed software is capable of calculating the theoretical bridge rating factors based on AASHTO Load and Resistance Factor Rating specifications, and automatically produces the field adjustment factor through load testing data. The sensing system along with its application in bridge deck rating was successfully demonstrated on the Evansville Bridge in West Virginia. A finite element model was conducted for the test bridge, and was used to calculate the load distribution factors of the bridge deck after verifying its results using field data. A confirmation field test was conducted on the same bridge and its results varied by only 3% from the first test. The proposed wireless sensing system proved to be a reliable tool that overcomes multiple drawbacks of conventional wired sensing platforms designed for structural load evaluation of bridges.

• The Journal of Asian Finance, Economics and Business
• /
• 제3권3호
• /
• pp.5-15
• /
• 2016

This study examines whether Korean rating agencies such as Korea Investors Service (KIS), National Information & Credit Evaluation (NICE), and Korea Ratings Corporation (KR), incorporate corporate governance into their corporate bond ratings in Korea. We find that the Korean rating agencies assign higher ratings to the bonds issued by Chaebol (Korean business group) affiliated firms. Our results also indicate that those rating agencies give higher ratings to the bonds with greater foreign investor share ownership. Moreover, if the rating agencies value corporate governance, higher rated firms should issue bonds at lower yield to maturity. We discover that Chaebol affiliation is counted favorably by the rating agencies. We find that investors are willing to pay lower risk premium for bonds with higher institutional ownership, but higher risk premium to bonds with greater equity ownership in the form of depository receipts. Therefore, even if the rating agencies and investors in Korea consider corporate governance (Chaebol affiliation and ownership structure) an important determinant in bond ratings and the yields to maturity, they have opposite views on institutional ownership and share ownership in the form of depository receipts.

• 한국수자원학회논문집
• /
• 제41권9호
• /
• pp.943-958
• /
• 2008

본 연구는 수위-유량 관계곡선식의 매개변수 추정을 수행하기 위하여 Bayesian 회귀분석을 적용하였다. 또한 불확실성측면에서의 효과를 탐색하기 위하여 Bayesian 회귀분석에 의한 추정치와 t 분포를 이용하여 산정한 일반 최소자승법(ordinary least square, OLS)에 의한 회귀분석의 추정치를 각각 산정하여 산정결과의 신뢰구간을 비교분석 하였다. 등분산케이스의 통계적 실험결과 t 분포를 이용하여 산정된 평균 추정치와 Bayesian 회귀분석에 의한 평균 추정치는 크게 다르지 않았으나, 비등분산 케이스의 경우에는 Bayesian 회귀분석이 참값에 가까운 추정치를 산정함을 알 수 있었다. 또한 불확실성 측면에서 평가해 볼 때 신뢰구간의 상한추정치와 하한추정치의 차이는 Bayesian 회귀분석을 사용한 경우가 기존 방법을 사용한 경우보다 작은 것으로 나타났으며, 이로부터 수위-유량 관계곡선식의 매개변수를 추정하는 경우 Bayesian 회귀분석이 일반 회귀분석보다 불확실성을 표현하는데 있어서 우수하다는 결과를 얻을 수 있었다. 적용된 두 가지의 추정방법은 비등분산성을 고려한 통계적 실험을 통하여 장점과 단점이 비교되었으며, 안양천 유역의 5개 지점으로부터 얻어진 유량측정성과를 이용하여 적용성을 알아보았다. 현장 적용결과는 참값을 알지 못하므로 정량적 우수성은 평가할 수 없었으나, 기존에 사용되는 불확실성 산정방법보다 Bayesian 회귀 분석 불확실성은 감소시켜 나타냄을 알 수 있었다.

• 한국구조물진단유지관리공학회 논문집
• /
• 제10권6호
• /
• pp.163-176
• /
• 2006

본 논문에서는 사장교 주요부재인 거더와 주탑 및 케이블의 내하율을 평가하기 위한 식을 제안하였다. 응력 및 안정성 검토식을 이용하여 강사장교 거더와 주탑에 적용 가능한 내하율 산정식을 제안하였고 케이블의 내하율 산정식을 제안하였다. 영향선해석을 수행하여 사장교 각 부재에 인장력 최대, 압축력 최대 및 정/부 모멘트 최대의 경우에 활하중 재하 형태를 결정하였고 각 부재의 내하율 산정절차를 정리하였다. 제안된 내하율 산정방법의 타당성을 검증하기 위하여 실교량 모델인 돌산대교에 대한 적용예를 제시하였다. 일반교량의 내하율 산정방법은 돌산대교 거더와 주탑의 내하율을 과대 평가 하였으며, 제안된 내하율 산정방법은 축력과 모멘트를 동시에 지지하는 사장교 거더와 주탑의 거동을 적절히 반영하였다.

• Asian Journal of Business Environment
• /
• 제8권1호
• /
• pp.23-29
• /
• 2018

Purpose - The purpose of this research is to make a comparative assessment of People Credit Funds (PCFs) ranking in Vietnam between the Circular No. 42/2016/TT-NHNN dated December 20, 2016 with the Decision No. 14/2007/QD-NHNN dated 09/4/2007 issued by the Governor of the State Bank. Research design, data, and methodology - This study is mainly based on the Circular No. 42/2016/TT-NHNN dated December 20, 2016 and the Decision No. 14/2007/QD-NHNN dated 09/4/2007 issued by the Governor of the State Bank on PCFs ranking. Results - The study paper has shown positive changes in PCFs ranking in Vietnam in accordance with the Circular No. 42/2016/TT-NHNN, such as increasing Capital Adequacy Ratio (CAR), maintaining CAR, improving assets quality, developing indicators of governance, management and control capability. These changes have implications for the development and efficient performance of PCFs in Vietnam. Conclusions - The classification and evaluation of PCFs will contribute to its healthy development. These finding support PCFs to understand more about rating methodology, significance of rating system and the importance of improving their rating. PCFs in Vietnam desire to develop their business effectively, they need to understand exactly and comply fully with regulations related to their field of operations.

• Journal of Information Processing Systems
• /
• 제15권2호
• /
• pp.386-398
• /
• 2019

The transmission capacity of transmission lines is affected by environmental parameters such as ambient temperature, wind speed, wind direction and so on. The environmental parameters can be measured by the installed measuring devices. However, it is impossible to install the environmental measuring devices throughout the line, especially considering economic cost of power grid. Taking into account the limited number of measuring devices and the distribution characteristics of environment parameters and transmission lines, this paper first studies the environmental parameter estimating method of inverse distance weighted interpolation and ordinary Kriging interpolation. Dynamic thermal rating of transmission lines based on IEEE standard and CIGRE standard thermal equivalent equation is researched and the key parameters that affect the load capacity of overhead lines is identified. Finally, the distributed thermal rating of transmission line is realized by using the data obtained from China meteorological data network. The cost of the environmental measurement device is reduced, and the accuracy of dynamic rating is improved.