Relay Selection Considering Successive Packets Transmission in Cooperative Communication Networks

Relay selection has been regarded as an effective method to improve the performance of cooperative communication system. However, frequent operation of relay selection can bring enormous control message overhead and thereby decrease the performance of cooperative communication. To reduce the relay selection frequency, in this paper, we propose a relay selection scheme to choose the best relay with considering successive packets transmission. In this scheme, according to the length of data packet, data transmission rate and the estimated channel state information (CSI), the best relay is selected to maximize the number of successive packets transmission under the condition that the given symbol-error-rate (SER) is kept. Finally, numerical results show that the proposed relay selection scheme can support the operation of successive packets transmission in cooperative wireless networks and that the maximum number of successive packets transmission is affected by the different network parameters, i.e., data transmission rate, packet length and Doppler frequency at one relay node

Failure mechanism and practical load-carrying capacity calculation method of welded hollow spherical joints connected with circular steel tubes

p. 2679-2691According to the ultimate load-carrying capacity obtained from finite element analysis, data point is designed based on orthogonal method, utilizing F-inspection from mathematical statistics to perform multi-parameter and single-factor significance analysis of compressive load capacity. The result indicates that yield strength of spherical material fy are the critical factor that influence the load carrying capacity of hollow spherical joint, as well as wall thickness t, outer diameter of sphere D and outer diameter of steel tube d. Comparatively destructive experiments on 8 typical full-scale joints made from two different graded material, Q235B and Q345B, were conducted to understand directly the structural behavior and the collapse mechanism of the joint, and also to validate the finite element analysis and parameter study. Finally, the simplified theoretical solution is also derived for the loading-carrying capacity of the joint based on the punching shear failure model, and the basic form for the design equation is obtained. By applying the results from the simplified theoretical solution, finite element analysis and experimental study, and utilizing the theory of mathematic statistics and regression analysis, the practical calculation method is established for the load-carrying capacity of the joints subjected to axial compressive forces. By the check of large amount of experiment data, the calculation result obtained from this formula is consistent with experiment result, and the practical formula has safety reserve meeting the regulation in national codes. The achievements from this study can be applied for direct design , and also provide a reference for the revision of relevant design codes.Xue, W.; Yang, L.; Zhang, Q.; Wang, P. (2009). Failure mechanism and practical load-carrying capacity calculation method of welded hollow spherical joints connected with circular steel tubes. Editorial Universitat Politècnica de València. http://hdl.handle.net/10251/660

The influence of minimum wage regulation on labor income share and overwork: evidence from China

Minimum Wage Regulation (MWR) can raise wage rate, but its relation with labor income share is in controversy. We explore the influence of raising wage rate on labor income share and overwork in China. Panel data regressions are taken mainly based on China’s Industrial Enterprise Database and the International Labor Organization Database. Our findings show that raising wage rate can increase labor income share without leading to overwork. Factors that may significantly increase overwork are a higher proportion of male workers, a larger income gap and a lower percapita income. We point out that the neoclassical explanation for labor income share is not persuasive. We support policies of raising wage rate and believe MWR is an effective measure to increase labor income share