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This article describes the current state of computer Chinese chess (Xiang Qi). For two reasons, Chinese-chess programming is important in the field of Artificial Intelligence. First, Chinese chess is one of the most popular and oldest board games worldwide; currently the strength of a Chinesechess program can be compared to that of human players. Second, the complexity of Chinese chess is between that of chess and Go. We assume that after DEEP BLUE's victory over Kasparov in 1997, Chinese chess will be the next popular chess-like board game at which a program will defeat a human top player. In the article we introduce some techniques for developing Chinese-chess programs. In the Computer Olympiads of 2001 and 2002, the programs ELP and SHIGA were the top Chinese-chess programs. Although these two programs roughly have the same strength, they were developed following completely different techniques, as described in the article. The improvements of the best Chinese-chess programs over the last twenty years suggest that a human top player will be defeated before 2010. 1. Chinese chess is a two-player, zero-sum game with complete information. Chinese-chess expert knowledge started to be developed some 800 years ago. Nowadays, the world has many excellent human players. Yet, already now, the strength of the best Chinese-chess programs can be compared to that of human players notwithstanding the fact that the game is considered rather complex. Table 1 shows the state-space complexity and the game-tree complexity of chess, Chinese chess, Shogi, and Go. The state-space complexity of Western chess and Chinese chess was estimated by Allis (1994). The game-tree complexity of Chinese chess is based on a branching factor of 38 and an average game length of 95 plies (Hsu, 1990). The complexity of two other games has been estimated: by Bouzy and Cazenave (2001) for Go and by Iida, Sakuta, and Rollason (2002) for Shogi. The complexity of Chinese chess is between that of Western chess and Shogi. Game State-space complexity Game-tree complexity Chess 50 123 Chinese chess 48 150 Shogi 71 226 Go 160 400 Table 1: State-space complexity and game-tree complexity given by the power of 10.

Changes in vascular mechanics due to aging include elevated vascular impedance, diminished aorta distensibility, and an accelerated return of pulse wave reflection, which may increase the systolic workload on the heart. Classically, the accurate measurement of vascular mechanics requires the simultaneous recording of aortic pressure and flow signals. In practice, it is feasible to estimate arterial wave properties in terms of wave transit time (τw) and wave reflection index (RI) by using aortic pressure signal alone. In this study, we determined the τw and magnitudes of the forward (∣Pf∣) and backward (∣Pb∣) pressure waves in Long–Evans male rats aged 4 (n = 14), 6 (n = 17), 12 (n = 17), and 18 (n = 24) months, based on the measured aortic pressure and an assumed triangular flow (Qtri). The pulsatile pressure wave was the only signal recorded in the ascending aorta by using a high-fidelity pressure sensor. The base of the unknown Qtri was constructed using a duration, which equals to the ejection time. The timing at the peak of the triangle was derived using the fourth-order derivative of the aortic pressure waveform. In the 18-month-old rats, the ratio of τw to left ventricular ejection time (LVET) decreased, indicating a decline in the distensibility of the aorta. The increased ∣Pb∣ associated with unaltered ∣Pf∣ enhanced the RI in the older rats. The augmentation index (AI) also increased significantly with age. A significant negative correlation between the AI and τw/LVET was observed: AI = −0.7424 − 0.9026 × (τw/LVET) (r = 0.4901; P < 0.0001). By contrast, RI was positively linearly correlated with the AI as follows: AI = −0.4844 + 2.3634 × RI (r = 0.8423; P < 0.0001). Both the decreased τw/LVET and increased RI suggested that the aging process may increase the AI, thereby increasing the systolic hydraulic load on the heart. The novelty of the study is that Qtri is constructed using the measured aortic pressure wave to approximate its corresponding flow signal, and that calibration of Qtri is not essential in the analysis.

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Data presented in this article relates to the research article entitled “US-CAB protocol for ultrasonographic evaluation during cardiopulmonary resuscitation: validation and potential impact” (Lien et al., in press). The article provides data regarding proficiency of the 10 emergency residents attending the US-CAB curriculum. Assessments included immediate evaluation at the end of training and re-evaluation 6 months later. A written test, and the ultrasound image acquisition were required in the immediate evaluation The re-evaluation included the written test and performance on the same healthy volunteer.

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