975 resultados para Discrete Choice Experiment


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The mixture of the feces and urine of the red fox (Vulpes vulpes Linnaeus) was used to increase the perception of predation risk of plateau pikas (Ochotona curzoniae Hodgson) in the field. The influence of the predation risk on the reproduction and behavior of plateau pikas was examined through comparing reproductive characteristics and five different kinds of behavior between treatment and control plots. The results showed that 1) the body weight of the pikas was not significantly different between treatment and control plots. 2) The reproductive period of the pikas extended from March to later August in both treatment and control plots. The pregnant ratio, developed testes ratio, reproductive success and sex ratio of the pikas were not significantly different between the treatment and control plots. 3) The pikas increased their observing and calling frequencies and decreased their moving and feeding frequencies when exposed to red fox's feces and urine. 4) The increased red fox's feces and urine had no influence on the behavior of the pikas when the number of their natural enemies increased; the pikas obviously increased the observing frequencies and sharply decreased the calling frequency so as to decrease the direct predation risk. 5) There were no significantly behavioral differences between males and females as well as between adults and young. 6) The results reject the hypothesis 1 that the red fox's feces and urine as indirect predation risk suppresses the reproduction of the pikas and support the hypothesis 2 that the pikas can make decision by changing behavior to avoid the predation risk they encountered whenever.

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针对RFID读写器识别多标签过程中出现的冲突问题,研究并实现了EPC Class-1 Gen-2标准中的防冲突算法,即时隙随机算法(SR算法),同时针对SR算法的不足提出改进算法。改进算法采用不避让冲突时隙的处理方式,降低了由时隙的随机选取所导致的标签间冲突的概率。实验结果证明,改进后的算法在通信次数和吞吐率方面均优于原算法,有效提高标签识别效率。

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通过优化知识表达系统中条件属性对决策属性的依赖度,深入研究了粗糙集并与多Agent系统相结合。利用离散粒子群算法,提出一种基于粒子群优化的粗糙集知识约简算法,该算法解决了启发式算法无法全局搜索进行约简的问题。最后通过在矿井中调度信息的应用验证了有效性。

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There are two major problems that have been concerned all the times, which are the mechanics characters of joint rock mass and the criterion for stability of engineering rock. Aim at the two problems, several works were conducted as follow: (1) Firstly, the mechanics characters of rock mass was studied by means of the Distinct Element Code. Subsequently, it was studied that the sensibility of joint surface roughness, strength of joint wall, joint stiffness ( i.e. tangential and normal stiffness) on the rock mass strength. (2) Based on the experimental rock mass classification methods of RMR and GSI, the program of “Parameters Calculation of the Rock Mass ” was developed. It has realized the rapid choice of rock mass parameters. (3) The concept of Representive Element Volume was induced based on the study of dimensional effect of rock mass. The Representive Element Volume of the horizontal and vertical pillar (ab. Two Pillars ) in the 2nd zone of Jinchuan mine were gained by the Geology Statistic Method and the Distinct Element Code. And then, the strength and deformatiom parameters of rock mass of the Two Pillars were obtained through numerical experiment. (4) From the confining depressure after thriaxial compression test of rock sample, it was concluded that the failure of rock is caused mainly by the lateral deformation and energy release happened during the confining depressure processure. The criterion of plastic energy catastrophe of rock engineering failure was proposed and validated. Subsquently, the stability of the horizontal pillar and Qianjiangping landslide in Three Gorges was judged by means of above-mentioned method. (5) Based on the fact there is a phenomenon of increasing energy concentration while the rock mass was compressed, rock information entropy (i.e. energy distribution entropy) was proposed. And it was revealed that there was change of energy distribution entropy while the rock mass was compressed to failure.

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Choice conflict is a critical issue in decision making. This study adopted stock transaction as the task to explore the relation between share price level and conflict intensity that the subjects experienced in decision making, and the effect of price level on individual and group choice conflict resolution. The strategy people used to solve choice conflict and gender difference were also examined. Modes of interaction (face to face and through audio media) in group decision making were also studied. The main results are as follows: 1. In individual decision-marking, there is a significant gender effect on decision time. Female subjects will spent more time on the task than male subjects. 2. When making a choice decision, the individual experienced stronger conflict for price shares than for low price shares. The stronger the conflict level they feel, the more difficult to make the choice decision. 3. Four strategies were used to finish the task. Male subjects used simple strategies while female subjects used more complex strategies. 4. In group decision-making, share price level had a significant effect on selection time. People used longer selection time for low price shares than for high price shares. No significant interaction was found between share price level and Modes of interaction. 5. Modes of interaction had significant effect on satisfaction coherence of the group. Under face-to-face condition, people within one group had greater satisfaction coherence. 6. Media had no significant effect on people's perception during the experiment. Satisfaction for cooperation, successful communication and good cooperation were correlated. Self satisfaction and satisfaction of the partners others were also correlated with the satisfaction of the whole task.

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Data on meaning of working (MOW) were collected from 905 respondents in Beijing area through a stratified sampling procedure of the questionnaire used in the restudy of meaning of working (which is still on going, adapted for using in China). Some parts of the factor structure obtained in this study are similar to what found by the MOW International Research Team (1987). Detailed analysis and cross-cultural comparisons were concentrated on the most similar parts societal norms about working (SNW). T-scores of the obligation norm (ON) and entitlement norm (EN) of Chinese were calculated based on the reaction frequencies of relevant items provided by the MOW International Research Team and shown as follows. The results reveal the obligation orientation characteristic of Chinese respondents. And more, 4 SNW patterns of Chinese respondents were obtained through multivariate cluster analysis and multivariate discrimination analysis and shown as follows. The influences of antecedent variables on SNW and the consequences of SNW were analyzed. Two questions were raised from these analyses: 1) The present measurements of SNW are not able to reflect the nature of the relation and dependency between ON and EN and are not free from social desirability; 2) the relationship between SNW and actual working behaviors need to be tested while the relationship between SNW and several work intentions was confirmed. A forced-choice scale of SNW was designed to overcome the shortcomes of the original scale. This scale includes 30 items. Each item is composed of a ON statement and a EN statement with similar values of social desirability. A repertory grids test was used to exam the constructure validity and to analyze the differences of cognitive structures of the 4 SNW patterns. The results indicated that the new scale had a good discrimination power. An experiment was designed to test the relationship of SNW and the actual work behaviors of the respondents. The respondents' action in completing a task was chosen as working behavior index. 4 hypotheses were tested: 1) higher obligation orientation subjects are more likely to complete tasks no matter overtime; 2) scheduled tasks are more likely to be completed no matter overtime; 3) the obligation norm about working is positively correlated with general obligation norms; and, 4) external motivtors will enhance lower obligation orientation subjects' working motivation more than higher obligation orientation subjects' the results verified hypothesis 1 and 3, but didn't support hypothesis 2 and 4 these findings will have great implication in administrating.

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We consider the question "How should one act when the only goal is to learn as much as possible?" Building on the theoretical results of Fedorov [1972] and MacKay [1992], we apply techniques from Optimal Experiment Design (OED) to guide the query/action selection of a neural network learner. We demonstrate that these techniques allow the learner to minimize its generalization error by exploring its domain efficiently and completely. We conclude that, while not a panacea, OED-based query/action has much to offer, especially in domains where its high computational costs can be tolerated.