Current Issue : April - June Volume : 2014 Issue Number : 2 Articles : 6 Articles
We study the space that consists of all nonsingular binary matrices, that is, GLn(Z2). The space is quite important in that it is\r\nused for the change of basis in binary representation, which is the encoding typically adopted in genetic algorithms. We analyze\r\nthe properties of GLn(Z2) and theoretically design possible encodings and their corresponding recombination operators for\r\nevolutionary algorithms.We present approaches based on elementary matrices of linear algebra as well as typical two-dimensional\r\nones....
In practical structural health monitoring (SHM) process based on wireless sensor network (WSN), data loss often occurs during the\r\ndata transmission between sensor nodes and the base station, which will affect the structural data analysis and subsequent decision\r\nmaking. In this paper, a method of recovering lost data in WSN based on compressive sensing (CS) is proposed. Compared with\r\nthe existing methods, it is a simple and stable data recovery method and can obtain lower recovery data error for one-dimensional\r\nSHM�s data loss. First, response signal ?? is measured onto the measurement data vector ?? through inner products with random\r\nvectors. Note that ?? is the linear projection of ?? and ?? is permitted to be lost in part during the transmission. Next, when the\r\nbase station receives the incomplete data, the response signal ?? can be reconstructed from the data vector ?? using the CS method.\r\nFinally, the test of active structural damage identification on LF-21M aviation antirust aluminum plate is proposed. The response\r\nsignal gathered from the aluminum plate is used to verify the data recovery ability of the proposed method....
Due to the occurrence of abnormal global environmental change, the concept of sustainable development becomes more andmore\r\nimportant. Port plays an important role in economic development for a country. To tackle the environmental pollution coming from\r\nthe construction and operation of a port, the green concept emerged as a solution. Founded on the previous literatures, the current\r\nstudy formulates a Fuzzy AHP model including five dimensions and thirteen factors as the guidelines for green port operation.The\r\nresults of empirical study point out the top five priority attributes of green port operation which are: hazardous waste handling, air\r\npollution, water pollution, port greenery, and habitat quality maintenance.The FAHP model is a good referral for decision makers\r\nof port organizations to forge a ââ?¬Å?greenerââ?¬Â port operation; it also can be used to evaluate the portââ?¬â?¢s green operation performance....
Multi-spot-beam technique has been widely applied in modern satellite communication systems. However, the satellite power\r\nand bandwidth resources in a multi-spot-beam satellite communication system are scarce and expensive; it is urgent to utilize\r\nthe resources efficiently. To this end, dynamically allocating the power and bandwidth is an available way. This paper initially\r\nformulates the problem of resource joint allocation as a convex optimization problem, taking into account a compromise between\r\nthe maximum total system capacity and the fairness among the spot beams. A joint bandwidth and power allocation iterative\r\nalgorithm based on duality theory is then proposed to obtain the optimal solution of this optimization problem. Compared with the\r\nexisting separate bandwidth or power optimal allocation algorithms, it is shown that the joint allocation algorithm improves both\r\nthe total system capacity and the fairness among spot beams.Moreover, it is easy to be implemented in practice, as the computational\r\ncomplexity of the proposed algorithm is linear with the number of spot beams....
This paper applies recent research on structural damage description to earthquake-resistant design concepts. Based on the primary\r\ndesign aim of life safety, this work adopts the necessity of additional protection aims for property, installation, and equipment.\r\nThis requires the definition of damage indicators, which are able to quantify the arising structural damage. As in present design,\r\nit applies nonlinear quasistatic (pushover) concepts due to code provisions as simplified dynamic design tools. Substituting so\r\nnonlinear time-history analyses, seismic low-cycle fatigue of RC structures is approximated in similar manner.The treatment will\r\nbe embedded into a finite element environment, and the tangential stiffness matrix K?? in tangential subspaces then is identified as\r\nthe most general entry for structural damage information. Its spectra of eigenvalues ???? or natural frequencies ???? of the structure\r\nserve to derive damage indicators ????, applicable to quasistatic evaluation of seismic damage. Because det K?? = 0denotes structural\r\nfailure, such damage indicators range from virgin situation ???? = 0 to failure ???? = 1 and thus correspond with Fema proposals on\r\nperformance-based seismic design. Finally, the developed concept is checked by reanalyses of two experimentally investigated RC\r\nframes....
In spline rolling process, the billet is mainly driven by frictional moment at initial forming stage that from starting rolling to\r\nbillet/workpiece rotated half circle. If the rotation of billet is not normally driven by rolling die, then the motion between billet and\r\nrolling die is not coordinated, and then dividing precision of external spline will be reduced.Thus, the rotatory condition of rolled\r\nbillet was established in thiswork.Therotatory condition for the rolling process of spline with even number of teeth is different from\r\nthat with an odd number of teeth. However, the changing trends for both rotatory conditions are the same.The results indicated\r\nthat (i) the rotatory condition can be improved when the friction between die and billet increases or the outside diameter of rolling\r\ndie increases, (ii) the rotatory condition for odd number of teeth is better than that for even number of teeth, and (iii) the outside\r\ndiameter of rolling die should be five times greater than the diameter of billet before rolling according to the rotatory condition.\r\nThe reasonable decrement can be selected by comprehensive considering of rotatory condition and geometry of rolling die....
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