This paper proposes a voltage-based hot-spot detection method for defective cells in PV module using projector. The presence of internal crystal defects is one of the main causes of hot-spot phenomenon in PV modules. ...This paper proposes a voltage-based hot-spot detection method for defective cells in PV module using projector. The presence of internal crystal defects is one of the main causes of hot-spot phenomenon in PV modules. Authors previously investigated the physical characteristics of hot-spot phenomenon referring to internal crystal defect. Based on it, a hot-spot detection method named as current-based SRC （self reverse current） detection method is developed. However, it becomes extraordinarily complicated to determine the defective cells under low illumination. In order to avoid this disadvantage, authors improve the SRC detection method by applying voltage. From the feasibility experiment results, it is confirmed that by calculating cell HSI （hotspots index） with voltage, the PV modules with defective cells can be prospectively excluded even under low illumination.展开更多
Recently, foreign exchange rates have been highly volatile all over the world. This article reports on an empirical examination of the effectiveness of foreign exchange market intervention in Tokyo foreign exchange ma...Recently, foreign exchange rates have been highly volatile all over the world. This article reports on an empirical examination of the effectiveness of foreign exchange market intervention in Tokyo foreign exchange market. In Japan, intervention in the foreign exchange market has occurred frequently and largely. In 2010, exchange rates fluctuated greatly, and the Japanese yen appreciated greatly against other foreign currencies. The Bank of Japan （BOJ） conducted an intervention in the foreign exchange market and bought massive USD to weaken the yen. They are expected to prevent too much appreciation of the yen, to promote export, and expansion of the economy. Recent foreign exchange market intervention in Tokyo has been effective in preventing the Japanese yen from appreciating against other currencies. Also, unsterilization has had a positive effect on depreciation of the yen. Moreover, news announcements by the Bank of Japan （BOJ） has led to depreciation of the yen. Effective announcements would increase the effects on markets. Sterilization in intervention and market communication are both taken into account in this article. The BOJ＇s news announcements seem to convey to markets adequately and communication between the bank and markets functions well. Moreover, the past exchange rate （i.e., the signaling effect） also is important to the movement of exchange rates. On the other hand, portfolio channel is not found展开更多
A direct as well as iterative method(called the orthogonally accumulated projection method, or the OAP for short) for solving linear system of equations with symmetric coefficient matrix is introduced in this paper. W...A direct as well as iterative method(called the orthogonally accumulated projection method, or the OAP for short) for solving linear system of equations with symmetric coefficient matrix is introduced in this paper. With the Lanczos process the OAP creates a sequence of mutually orthogonal vectors, on the basis of which the projections of the unknown vectors are easily obtained, and thus the approximations to the unknown vectors can be simply constructed by a combination of these projections. This method is an application of the accumulated projection technique proposed recently by the authors of this paper, and can be regarded as a match of conjugate gradient method(CG) in its nature since both the CG and the OAP can be regarded as iterative methods, too. Unlike the CG method which can be only used to solve linear systems with symmetric positive definite coefficient matrices, the OAP can be used to handle systems with indefinite symmetric matrices. Unlike classical Krylov subspace methods which usually ignore the issue of loss of orthogonality, OAP uses an effective approach to detect the loss of orthogonality and a restart strategy is used to handle the loss of orthogonality.Numerical experiments are presented to demonstrate the efficiency of the OAP.展开更多
文摘本文研究Hilbert空间H上投影算子组的联合谱.首先通过计算给出正则投影对的联合谱,进而给出一般的投影算子对的联合谱.本文还对两个投影算子的和与差的可逆性给出一些等价刻画.特别地,当P和Q为正则投影对时,本文通过计算算子组[I, P, Q]的联合谱来给出σ(P+Q)和σ(P-Q)的具体刻画.反过来,本文证明两类具有特定形式的复数集分别是Hilbert空间上正则投影对的和与差的谱.本文也给出一般的投影算子对的和与差的谱.最后,本文计算特定条件下的3个投影算子组[P, Q, R]的联合谱.
文摘This paper proposes a voltage-based hot-spot detection method for defective cells in PV module using projector. The presence of internal crystal defects is one of the main causes of hot-spot phenomenon in PV modules. Authors previously investigated the physical characteristics of hot-spot phenomenon referring to internal crystal defect. Based on it, a hot-spot detection method named as current-based SRC （self reverse current） detection method is developed. However, it becomes extraordinarily complicated to determine the defective cells under low illumination. In order to avoid this disadvantage, authors improve the SRC detection method by applying voltage. From the feasibility experiment results, it is confirmed that by calculating cell HSI （hotspots index） with voltage, the PV modules with defective cells can be prospectively excluded even under low illumination.
文摘Recently, foreign exchange rates have been highly volatile all over the world. This article reports on an empirical examination of the effectiveness of foreign exchange market intervention in Tokyo foreign exchange market. In Japan, intervention in the foreign exchange market has occurred frequently and largely. In 2010, exchange rates fluctuated greatly, and the Japanese yen appreciated greatly against other foreign currencies. The Bank of Japan （BOJ） conducted an intervention in the foreign exchange market and bought massive USD to weaken the yen. They are expected to prevent too much appreciation of the yen, to promote export, and expansion of the economy. Recent foreign exchange market intervention in Tokyo has been effective in preventing the Japanese yen from appreciating against other currencies. Also, unsterilization has had a positive effect on depreciation of the yen. Moreover, news announcements by the Bank of Japan （BOJ） has led to depreciation of the yen. Effective announcements would increase the effects on markets. Sterilization in intervention and market communication are both taken into account in this article. The BOJ＇s news announcements seem to convey to markets adequately and communication between the bank and markets functions well. Moreover, the past exchange rate （i.e., the signaling effect） also is important to the movement of exchange rates. On the other hand, portfolio channel is not found
基金supported by National Natural Science Foundation of China (Grant Nos. 91430108 and 11171251)the Major Program of Tianjin University of Finance and Economics (Grant No. ZD1302)
文摘A direct as well as iterative method(called the orthogonally accumulated projection method, or the OAP for short) for solving linear system of equations with symmetric coefficient matrix is introduced in this paper. With the Lanczos process the OAP creates a sequence of mutually orthogonal vectors, on the basis of which the projections of the unknown vectors are easily obtained, and thus the approximations to the unknown vectors can be simply constructed by a combination of these projections. This method is an application of the accumulated projection technique proposed recently by the authors of this paper, and can be regarded as a match of conjugate gradient method(CG) in its nature since both the CG and the OAP can be regarded as iterative methods, too. Unlike the CG method which can be only used to solve linear systems with symmetric positive definite coefficient matrices, the OAP can be used to handle systems with indefinite symmetric matrices. Unlike classical Krylov subspace methods which usually ignore the issue of loss of orthogonality, OAP uses an effective approach to detect the loss of orthogonality and a restart strategy is used to handle the loss of orthogonality.Numerical experiments are presented to demonstrate the efficiency of the OAP.
