• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.5
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• pp.121-127
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• 2013

When input power is small, nonideal symmetric balance incomplete block design(BIBD) code design is effective in the spectral-amplitude-code(SAC) optical code-division multiple-access (OCDMA) system. But the number of simultaneous users is not sufficient. To overcome this property, we propose 2-D BIBD codes, where nonideal BIBD codes are used as spectral code and ideal BIBD codes are used as spatial codes. Analytical results show that the number of simultaneous users increases significantly.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.2
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• pp.119-124
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• 2015

In this paper, we analyze the effect of line-width of optical sources on the performance of spectral amplitude coding (SAC) optical code division multiple-access (OCDMA) systems. For a performance analysis we use a symmetric balanced incomplete block design (BIBD) code as the code sequence because we can construct a series of code families by choosing different values of q and m. The ideal BIBD code (m=2) requires narrower line-width than the nonideal BIBD codes when the effective power is large ($P_{sr}=-10dBm$). But the nonideal BIBD codes (m>2) need narrower line-width than the ideal BIBD code when $P_{sr}=-25dBm$.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.1
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• pp.117-123
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• 2013

By calculating the spectral efficiency of symmetric balance incomplete block design(BIBD) codes satisfying BER=$10^{-9}$, it can be found that ideal BIBD code design with m=2 and various q's is effective when effective power is high($P_{sr}=-10$ dBm). But BIBD code design with q > 2 and various m's can be effective when effective power is low($P_{sr}=-25$ dBm).

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.49 no.5
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• pp.22-29
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• 2012

By using the cyclic properties of symmetric balance incomplete block design(BIBD) codes and arrayed-waveguide grating(AWG) routers, a compact optical CDMA network coder-decoder(codec) can be constructed. It can be observed that the various code families obtained by BIBD improve the BER performance compared to M-sequence code.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.46 no.6
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• pp.79-86
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• 2009

In this paper, it has the performance metrics and the utility evaluation of the collusion codes about multimedia fingerprinting code based on BIBD and then the tracing algorithm of all colluders is proposed. Among the collusion codes, the bit stream of "all 0" or "all 1" are generated, also same collusion code and bit reversed code with user's fingerprinting code are generated. Thus there was occurred some problems, in which a colluder is deciding to anti-colluder or anti-colluder is deciding to colluder. In this paper, for the performance metrics and the utility evaluation of the collude codes, the experiment onto the total solution is processed by the logical collusion operation added with a partially processed averaging attack in the past papers. The proposed performance metrics and the utility evaluation about the collusion code generated from multimedia fingerprinting code based on BIBD is operated. Through the experiment, it confirmed that the ratio of colluder tracing is 100%.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.48 no.6
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• pp.1-8
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• 2011

In multimedia fingerprinting field, it is many used a code based on BIBD, which has a strong resiliency of anti-collusion. When a collusion-attack code is generated with a logical XOR operation using the code based on BIBD, then some cases are occurred that a colluded code could be generated to the same fingerprint of non-colluder on the other hand, the colluder is decided to the non-colluder so that he would be excepted in the colluder tracing. For solving the serious problem of the wrong decision of the colluder tracing in this paper, XOR-ACC is implemented using multi-layer perceptron neural network among (AND, OR, XOR and Averaging)-ACC by the measured correlation coefficient. Through the experiment, it confirms that XOR-ACC efficiency of multimedia fingerprinting code{7,3,1} based on BIBD is improved to 88.24% from the conventional 41.18%, so that a ratio of the colluder tracing is also improved to 100% from the conventional 53%. As a result, it could be traced and decided completely a sectional colluder and non-colluder about the collusion attacks.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.48 no.4
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• pp.27-34
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• 2011

In this paper, it was presented a design on the dynamic multimedia fingerprinting code for anti-collusion code(ACC) in the protection of multimedia content. Multimedia fingerprinting code for the conventional ACC, is designed with a mathematical method to increase k to k+1 by transform from BIBD's an incidence matrix to a complement matrix. A codevector of the complement matrix is allowanced fingerprinting code to a user' authority and embedded into a content. In the proposed algorithm, the feature points were drawing from a content which user bought, with based on these to design the dynamical multimedia fingerprinting code. The candidate codes of ACC which satisfied BIBD's v and k+1 condition is registered in the codebook, and then a matrix is generated(Below that it calls "Rhee matrix") with ${\lambda}+1$ condition. In the experimental results, the codevector of Rhee matrix based on a feature point of the content is generated to exist k in the confidence interval at the significance level ($1-{\alpha}$). Euclidean distances between row and row and column and column each other of Rhee matrix is working out same k value as like the compliment matrices based on BIBD and Graph. Moreover, first row and column of Rhee matrix are an initial firing vector and to be a forensic mark of content protection. Because of the connection of the rest codevectors is reported in the codebook, when trace a colluded code, it isn't necessity to solve a correlation coefficient between original fingerprinting code and the colluded code but only search the codebook then a trace of the colluder is easy. Thus, the generated Rhee matrix in this paper has an excellent robustness and fidelity more than the mathematically generated matrix based on BIBD as ACC.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.4
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• pp.27-32
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• 2014

Two-dimensional hybrid codewords are generated by using each row of identity matrix for spatial encoding and nonideal symmetric balance incomplete block design(BIBD) code for spectral encoding. This spatial/spectral optical code-division multiple-access (OCDMA) network uses single-balanced detectors to abstract the desired information bits and to eliminate the multiple-access interference(MAI). Analytical results show that the number of simultaneous users increases significantly by using the proposed hybrid codes.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.47 no.6
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• pp.1-7
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• 2010

This paper presents a novel implementation on multimedia fingerprinting algorithm based on BCH (Bose-Chaudhuri-Hocquenghem) code. The evaluation is put in force the colluder detection to n-1. In the proposed algorit hm, the used collusion attacks adopt logical combinations (AND, OR and XOR) and average computing (Averaging). The fingerprinting code is generated as below step: 1. BIBD {7,4,1} code is generated with incidence matrix. 2. A new encoding method namely combines BIBD code with BCH code, these 2 kind codes are to be fingerprinting code by BCH encoding process. 3. The generated code in step 2, which would be fingerprinting code, that characteristic is similar BCH {15,7} code. 4. With the fingerprinting code in step 3, the collusion codebook is constructed for the colluder detection. Through an experiment, it confirmed that the ratio of colluder detection is 86.6% for AND collusion, 32.8% for OR collusion, 0% for XOR collusion and 66.4% for Averaging collusion respectively. And also, XOR collusion could not detect entirely colluder and on the other hand, AND and Averaging collusion could detect n-1 colluders and OR collusion could detect k colluders.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.43 no.5 s.311
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• pp.68-75
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• 2006

Multimedia fingerprinting protects multimedia content from illegal redistribution by uniquely marking every copy of the content distributed to each user. Differ from a symmetric/asymmetric scheme, fingerprinting schemes, only regular user can know the inserted fingerprint data and the scheme guarantee an anonymous before recontributed data. In this paper, we present a scheme which is the algorithm using LDPC(Low Density Parity Check) for detection of colluded multimedia fingerprint and correcting errors. This proposed scheme is consists of the LDPC block, Hopfield Network and the algorithm of anti-collusion code generation. Anti-collusion code based on BIBD(Balanced Incomplete Block Design) was made 100% collusion code detection rate about the linear collusion attack(average, AND and OR) and LD% block for the error bits correction confirmed that can correct error until AWGN 0dB.