332 research outputs found

    Valuing Studentsā€™ Cultural Experiences and Linguistic Abilities In the Classroom

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    English Language Learners (ELL) and students represented in culturally diverse communities are the fastest growing groups in US public schools (Samway & McKeon, 2007). Mainstream classrooms often struggle to meet the needs of Linguistically and Culturally Diverse (LCD) students, trying to connect instruction to studentsā€™ linguistic backgrounds or cultural experiences (Darder, 1991). Unfortunately, the education of LCD students has become exercises of ā€œdrill and killā€ and highly scripted instruction (Darder & Torres, 2004). This article explores reasons why studentsā€™ cultural experiences and linguistic abilities are not recognized in mainstream classrooms in an era of high-stakes testing. Additionally, the article will peer into the role of teachers in meeting the needs of LCD student populations when they are often times presented with scripted or scripted curricula

    Remarks on a cyclotomic sequence

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    We analyse a binary cyclotomic sequence constructed via generalized cyclotomic classes by Bai et al. (IEEE Trans Inforem Theory 51: 1849-1853, 2005). First we determine the linear complexity of a natural generalization of this binary sequence to arbitrary prime fields. Secondly we consider k-error linear complexity and autocorrelation of these sequences and point out certain drawbacks of this construction. The results show that the parameters for the sequence construction must be carefully chosen in view of the respective application

    Continued fraction for formal laurent series and the lattice structure of sequences

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    Besides equidistribution properties and statistical independence the lattice profile, a generalized version of Marsaglia's lattice test, provides another quality measure for pseudorandom sequences over a (finite) field. It turned out that the lattice profile is closely related with the linear complexity profile. In this article we give a survey of several features of the linear complexity profile and the lattice profile, and we utilize relationships to completely describe the lattice profile of a sequence over a finite field in terms of the continued fraction expansion of its generating function. Finally we describe and construct sequences with a certain lattice profile, and introduce a further complexity measure

    Remarks on the k-error linear complexity of p(n)-periodic sequences

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    Recently the first author presented exact formulas for the number of 2āæn-periodic binary sequences with given 1-error linear complexity, and an exact formula for the expected 1-error linear complexity and upper and lower bounds for the expected k-error linear complexity, k >2, of a random 2āæn-periodic binary sequence. A crucial role for the analysis played the Chan-Games algorithm. We use a more sophisticated generalization of the Chan-Games algorithm by Ding et al. to obtain exact formulas for the counting function and the expected value for the 1-error linear complexity for pāæn-periodic sequences over Fp, p prime. Additionally we discuss the calculation of lower and upper bounds on the k-error linear complexity of pāæn-periodic sequences over Fp

    Error linear complexity measures for multisequences

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    Complexity measures for sequences over finite fields, such as the linear complexity and the k-error linear complexity, play an important role in cryptology. Recent developments in stream ciphers point towards an interest in word-based stream ciphers, which require the study of the complexity of multisequences. We introduce various options for error linear complexity measures for multisequences. For finite multisequences as well as for periodic multisequences with prime period, we present formulas for the number of multisequences with given error linear complexity for several cases, and we present lower bounds for the expected error linear complexity

    On the linear complexity of Sidel'nikov Sequences over Fd

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    We study the linear complexity of sequences over the prime field Fd introduced by Sidelā€™nikov. For several classes of period length we can show that these sequences have a large linear complexity. For the ternary case we present exact results on the linear complexity using well known results on cyclotomic numbers. Moreover, we prove a general lower bound on the linear complexity profile for all of these sequences. The obtained results extend known results on the binary case. Finally we present an upper bound on the aperiodic autocorrelation

    Idempotent and p-potent quadratic functions: distribution of nonlinearity and co-dimension

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    The Walsh transform QĖ†Q^ of a quadratic function Q:Fpnā†’FpQ:Fpnā†’Fp satisfies |QĖ†(b)|āˆˆ{0,pn+s2}|Q^(b)|āˆˆ{0,pn+s2} for all bāˆˆFpnbāˆˆFpn , where 0ā‰¤sā‰¤nāˆ’10ā‰¤sā‰¤nāˆ’1 is an integer depending on Q. In this article, we study the following three classes of quadratic functions of wide interest. The class C1C1 is defined for arbitrary n as C1={Q(x)=Trn(āˆ‘āŒŠ(nāˆ’1)/2āŒ‹i=1aix2i+1):aiāˆˆF2}C1={Q(x)=Trn(āˆ‘i=1āŒŠ(nāˆ’1)/2āŒ‹aix2i+1):aiāˆˆF2} , and the larger class C2C2 is defined for even n as C2={Q(x)=Trn(āˆ‘(n/2)āˆ’1i=1aix2i+1)+Trn/2(an/2x2n/2+1):aiāˆˆF2}C2={Q(x)=Trn(āˆ‘i=1(n/2)āˆ’1aix2i+1)+Trn/2(an/2x2n/2+1):aiāˆˆF2} . For an odd prime p, the subclass DD of all p-ary quadratic functions is defined as D={Q(x)=Trn(āˆ‘āŒŠn/2āŒ‹i=0aixpi+1):aiāˆˆFp}D={Q(x)=Trn(āˆ‘i=0āŒŠn/2āŒ‹aixpi+1):aiāˆˆFp} . We determine the generating function for the distribution of the parameter s for C1,C2C1,C2 and DD . As a consequence we completely describe the distribution of the nonlinearity for the rotation symmetric quadratic Boolean functions, and in the case p>2p>2 , the distribution of the co-dimension for the rotation symmetric quadratic p-ary functions, which have been attracting considerable attention recently. Our results also facilitate obtaining closed formulas for the number of such quadratic functions with prescribed s for small values of s, and hence extend earlier results on this topic. We also present the complete weight distribution of the subcodes of the second order Reedā€“Muller codes corresponding to C1C1 and C2C2 in terms of a generating function

    Multisequences with high joint nonlinear complexity

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    We introduce the new concept of joint nonlinear complexity for multisequences over finite fields and we analyze the joint nonlinear complexity of two families of explicit inversive multisequences. We also establish a probabilistic result on the behavior of the joint nonlinear complexity of random multisequences over a fixed finite field
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