Initialize the Weights

A 10 x 10 SOM trained on values taken at random from a 1 x 1 square (a) at the start of training, (b) when training is complete. 

---

Initialize the weights with small random values in a range around 0 (e.g. -0.3 to +0.3). 

Initialize the weight vectors of all units with random values. 

Initialize the weights of all units (in a (pxc) matrix W) with a fixed value. The parameter p is the length of the weight vector and c is the total number of units. Usually the fixed value is used for the initial weights, such that the length of the weight vector is scaled to unity. 

Initialize the weights to small random numbers, usually between 0 and 1. The weight between input unit i and grid node j is wy. 

We have seen that the NN represents a complicated nested function, whose output depends on a set of weight parameters. Initially, the weight... 

Once numerical estimates of the weight of a trajectory and its variance (2cr ) are known we are able to use sampled trajectories to compute observables of interest. One such quantity on which this section is focused is the rate of transitions between two states in the system. We examine the transition between a domain A and a domain B, where the A domain is characterized by an inverse temperature - (3. The weight of an individual trajectory which is initiated at the A domain and of a total time length - NAt is therefore... 

The network is initialized, and all the weights of the neurons obtain numerical values, in most cases random numbers. 

A simpler approach for analyzing neutron activation data is to use one or more external standards. Letting Ao) and (Aq) represent the initial activity for the analyte in an unknown and a single external standard, and letting and represent the weight of analyte in the unknown and the external standard, gives a pair of equations... 

Soum and Fontanillet prepared a living polymer of 2-vin yl pyridine using benzyl picolyl magnesium as the initiator. The values of were measured experimentally for polymers prepared with different concentrations of initiator and different initial concentrations of monomer. The results are given below calculate the theoretical molecular weights expected if polymerization proceeds completely from 100% predissociated initiator and compare the theoretical and experimental values ... 

The weight percent propylene in ethylene-propylene copolymers for different Ziegler-Natta catalysts was measuredt for the initial polymer produced from identical feedstocks. The following results were obtained ... 

Because of the extreme accuracy expected of many of these products, some include internal test weights which can be used to recaUbrate regularly and to adjust for nonlinearity. Some balances monitor changing conditions and initiate the recahbration procedure as needed. 

In a typical adiabatic polymerization, approximately 20 wt % aqueous acrylamide is charged into a stainless steel reactor equipped with agitation, condenser, and cooling jacket or coils. To initiate the polymerization, an aqueous solution of sodium bisulfite [7631-90-5] is added, followed by the addition of a solution of ammonium persulfate [7727-54-0] N2HgS20g. As the polymerization proceeds, the temperature rises to about 90°C, and then begins to fall at the end of the polymerization. The molecular weight obtained depends primarily on the initiator concentration employed. 

The type of initiator utilized for a solution polymerization depends on several factors, including the solubiUty of the initiator, the rate of decomposition of the initiator, and the intended use of the polymeric product. The amount of initiator used may vary from a few hundredths to several percent of the monomer weight. As the amount of initiator is decreased, the molecular weight of the polymer is increased as a result of initiating fewer polymer chains per unit weight of monomer, and thus the initiator concentration is often used to control molecular weight. Organic peroxides, hydroperoxides, and azo compounds are the initiators of choice for the preparations of most acryUc solution polymers and copolymers. 

Aromatic radical anions, such as lithium naphthalene or sodium naphthalene, are efficient difunctional initiators (eqs. 6,7) (3,20,64). However, the necessity of using polar solvents for their formation and use limits their utility for diene polymerization, since the unique abiUty of lithium to provide high 1,4-polydiene microstmcture is lost in polar media (1,33,34,57,63,64). Consequentiy, a significant research challenge has been to discover a hydrocarbon-soluble dilithium initiator which would initiate the polymerization of styrene and diene monomers to form monomodal a, CO-dianionic polymers at rates which are faster or comparable to the rates of polymerization, ie, to form narrow molecular weight distribution polymers (61,65,66). 

Recently, composite wheels have become popular. While composite wheels may eliminate the use of spokes, they are costly and do not necessarily reduce the weight of the wheel or the energy necessary to initiate revolution. As a result, composite wheels do not always provide an adequate alternative to wheel covers as they may not be readily applicable to all uses in which spoke wheels may be found. Traditional spoke wheels are still the predominant wheel system for most two-wheeled vehicles. 

---