The Moments of a Kloosterman Sum and the Weight Distribution of a Zetterberg-Type Binary Cyclic Code

2007 ◽  
Vol 53 (2) ◽  
pp. 843-847 ◽  
Author(s):  
Marko J. Moisio
Author(s):  
C.A. Vázquez-Fernández ◽  
G. Vega-Hernández

 An important family of codes for error control in digital communications are the so-called cyclic codes; therefore, finding the weight distribution of a q-ary cyclic code C is not only a problem of theoretical interest, but also of practical importance. Typically, when the finite field q is a prime field, the problem is handled by expressing the Hamming weight of each codeword in C by means of certain combination of exponential sums. In this work, we will present a new method for computing the weight distribution of the dual of some cyclic codes with two non conjugated zeros. As we will see, such distribution is also given by means of the evaluation of certain exponential sums, however, such evaluation is only needed to be done over a subset. Moreover, this method has the advantage of flexibility, in the sense that it can also be applied to cyclic codes over finite fields of non prime order.


2013 ◽  
Vol 10 (2) ◽  
pp. 29
Author(s):  
Normah Ismail ◽  
Nur' Ain Mohamad Kharoe

Unripe and ripe bilimbi (Averrhoa bilimbi L.) were ground and the extracted juices were partially purified by ammonium sulfate precipitation at the concentrations of 40 and 60% (w/v). The collected proteases were analysed for pH, temperature stability, storage stability, molecular weight distribution, protein concentration and protein content. Protein content of bilimbi fruit was 0.89 g. Protease activity of both the unripe and ripe fruit were optimum at pH 4 and 40°C when the juice were purified at 40 and 60% ammonium sulfate precipitation. A decreased in protease activity was observed during the seven days of storage at 4°C. Molecular weight distribution indicated that the proteases protein bands fall between IO to 220 kDa. Protein bands were observed at 25, 50 and 160 kDa in both the unripe and ripe bilimbi proteases purified with 40% ammonium sulfate, however, the bands were more intense in those from unripe bilimbi. No protein bands were seen in proteases purified with 60% ammonium sulfate. Protein concentration was higher for proteases extracted with 40% ammonium sulfate at both ripening stages. Thus, purification using 40% ammonium sulfate precipitation could be a successful method to partially purify proteases from bilimbi especially from the unripe stage. 


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