• Proceedings of the IEEK Conference
• /
• 2002.06d
• /
• pp.9-12
• /
• 2002

In this Paper, we propose an efficient de-interlacing algorithm using temporal and spatial domain information. In the proposed scheme, motion estimation is performed same parity fields, i.e., if current field is even field, reference fields are previous even field and forward even field. And then motion vector refinement is performed to improve the accuracy of motion vectors. In the interpolating step, we use median filter to reduce the interpolation error caused by incorrect motion vector. Simulations conducted for various video sequences have shown the efficiency of the proposed interpolator with significant improvement over previous methods in terms of both PSNR and perceived image quality.

• Journal of Broadcast Engineering
• /
• v.25 no.1
• /
• pp.36-47
• /
• 2020

The improved belief-propagation-based algorithms, such as normalized min-sum algorithm (NMSA) or offset min-sum algorithm (OMSA), are widely used to decode LDPC(Low-Density Parity-Check) codes because they are less computationally complex and work well even at low SNR(Signal-to-Noise Ratio). However, these algorithms work well only when an appropriate normalization factor or offset value is used. A new method that uses a CMD(Check Node Message Distribution) chart and least-square method, which has been recently proposed, has advantages on computational complexity over other approaches to get optimal coefficients. Furthermore, this method can be used to derive coefficients for each iteration. In this paper, we apply this method and propose an algorithm to derive a combination of normalization factor and offset value for a combined normalized and offset min-sum algorithm to further improve the decoding of LDPC codes. Simulations on the next-generation broadcasting standards, ATSC 3.0 LDPC codes, prove that a combined normalized and offset min-sum algorithm which takes the proposed coefficients as correction coefficients shows the best BER performance among other decoding algorithms.

• Journal of IKEEE
• /
• v.3 no.1 s.4
• /
• pp.22-28
• /
• 1999

The existing CREG-VP, a technique to compensate the successive cell losses caused by traffic congestion using the FEC method on the Vp, has the merits of the short average encoding decoding time and the compatibility with the ATM standard cell format, but it has the restriction in the number of regenerable cells. In this thesis, we propose a scheme to efficiently regenerate the cell losses even in the burst traffic property by the expansion of the CREG-VP. The proposed scheme improves the detection capability of the lost cells by changing the CRP and the regeneration performance of the successive cells by using the interleaved parity cell. The simulation result shows that the proposed method produces much improvements compared with the existing ones in the cell loss rate reduction factor.

• Journal of Korea Multimedia Society
• /
• v.2 no.4
• /
• pp.490-495
• /
• 1999

In this paper, a method of improving the learning time and convergence rate is proposed to exploit the advantages of artificial neural networks and fuzzy theory to neuron structure. This method is applied to the XOR Problem, n bit parity problem which is used as the benchmark in neural network structure, and recognition of digit image in the vehicle plate image for practical image application. As a result of the experiments, it does not always guarantee the convergence. However, the network showed improved the teaming time and has the high convergence rate. The proposed network can be extended to an arbitrary layer Though a single layer structure Is considered, the proposed method has a capability of high speed 3earning even on large images.

• Journal of the Korean Society of Industry Convergence
• /
• v.3 no.2
• /
• pp.167-178
• /
• 2000

Software RAID(Redundant Arrays of Inexpensive Disks) is defined as a storage system that provides capabilities of hardware RAID, and guarantees high reliability as well as high performance. In this paper, we propose an enhanced disk scheduling algorithm and a scheme to guarantee reliability of data. We also design and implement software RAID by utilizing these mechanism to develop a storage system for multimedia applications. Because the proposed algorithm improves a defect of traditional GSS algorithm that disk I/O requests arc served in a fixed order, it minimizes buffer consumption and reduces the number of deadline miss through service group exchange. Software RAID also alleviates data copy overhead during disk services by sharing kernel memory. Even though the implemented software RAID uses the parity approach to guarantee reliability of data, it adopts different data allocation scheme. Therefore, we reduce disk accesses in logical XOR operations to compute the new parity data on all write operations. In the performance evaluation experiments, we found that if we apply the proposed schemes to implement the Software RAID, it can be used as a storage system for small-sized video-on-demand servers.

• Journal of Communications and Networks
• /
• v.11 no.6
• /
• pp.538-543
• /
• 2009

A wiretap channel I is one of the channel models that was proved to achieve unconditional security. However, it has been an open problem in realizing such a channel model in a practical network environment. The paper is committed to solve the open problem by introducing a novel approach for building wiretap channel I in which the eavesdropper sees a binary symmetric channel (BSC) with error probability p while themain channel is error free. By taking advantage of the feedback and low density parity check (LDPC) codes, our scheme adds randomness to the feedback signals from the destination for keeping an eavesdropper ignorant; on the other hand, redundancy is added and encoded by the LDPC codes such that a legitimate receiver can correctly receive and decode the signals. With the proposed approach, unconditionallysecure communication can be achieved through interactive communications, in which the legitimate partner can realize the secret information transmission without a pre-shared secret key even if the eavesdropper has better channel from the beginning.

• Journal of Communications and Networks
• /
• v.17 no.4
• /
• pp.339-345
• /
• 2015

In this paper, we present an iterative reliability-based modified majority-logic decoding algorithm for two classes of structured low-density parity-check codes. Different from the conventional modified one-step majority-logic decoding algorithms, we design a turbo-like iterative strategy to recover the performance degradation caused by the simply flipping operation. The main computational loads of the presented algorithm include only binary logic and integer operations, resulting in low decoding complexity. Furthermore, by introducing the iterative set, a very small proportion (less than 6%) of variable nodes are involved in the reliability updating process, which can further reduce the computational complexity. Simulation results show that, combined with the factor correction technique and a well-designed non-uniform quantization scheme, the presented algorithm can achieve a significant performance improvement and a fast decoding speed, even with very small quantization levels (3-4 bits resolution). The presented algorithm provides a candidate for trade-offs between performance and complexity.

• Journal of Arbitration Studies
• /
• v.27 no.1
• /
• pp.3-35
• /
• 2017

For recent years, several disputes between Korean consumers and multinational companies have arisen. Since the disputes were big and material that children's safety was at issue, a question started if Korean law properly has protected consumers' rights against multinational companies. While the Korean legal society tried to legislate punitive compensation with this concern, the U.S. Supreme Court reached an interesting case law regarding consumer contracts. A recent trend on consumer contracts in the United States shows that general terms have arbitration clause with class action waiver. As much as international arbitration has worked as the most effective resolution in international commercial disputes, the concept is still foreign and the experts are not approachable to lay individual consumers. However, class action in arbitration can hugely help for lay individual consumers to bring a case before arbitration tribunal. California courts consistently showed the analysis that the practical impact of prohibiting class action in arbitration clause is to ban lay individual consumers from fighting for their rights. However, the Supreme Court held that the arbitration clause shall be enforced as parties agree even if consumers practically cannot fight for their rights in the end. Even though consumer contracts are a typical example of lack of parity and of adhesive contract, the Supreme Court still applies liberalism that parties are equal in power and free to agree. This case law has a crucial implication since Korean consumers buy goods and services from the U.S. and other countries in everyday life. Accordingly, they are deemed to agree on the dispute resolution clauses, which might violate their constitutional right to bring their cases before the adjudication tribunal. This issue could be more important than adopting punitive compensation because consumers' rights are not necessarily governed by Korean law but by the governing law of the general terms and conditions chosen and written by the multinational companies. Thus this paper studies and analyzes the practical reality of international arbitration and influence of arbitration clause with class action waiver with the U.S. Supreme Court and California case laws.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.10 no.5
• /
• pp.409-416
• /
• 2017

In this paper, we consider a framework of compressed sensing over finite fields. One measurement sample is obtained by an inner product of a row of a sensing matrix and a sparse signal vector. A recovery algorithm proposed in this study for sparse signals based probabilistic decoding is used to find a solution of compressed sensing. Until now compressed sensing theory has dealt with real-valued or complex-valued systems, but for the processing of the original real or complex signals, the loss of the information occurs from the discretization. The motivation of this work can be found in efforts to solve inverse problems for discrete signals. The framework proposed in this paper uses a parity-check matrix of low-density parity-check (LDPC) codes developed in coding theory as a sensing matrix. We develop a stochastic algorithm to reconstruct sparse signals over finite field. Unlike LDPC decoding, which is published in existing coding theory, we design an iterative algorithm using probability distribution of sparse signals. Through the proposed recovery algorithm, we achieve better reconstruction performance as the size of finite fields increases. Since the sensing matrix of compressed sensing shows good performance even in the low density matrix such as the parity-check matrix, it is expected to be actively used in applications considering discrete signals.

• The Korean Journal of Financial Management
• /
• v.6 no.1
• /
• pp.31-62
• /
• 1989

By using deterministic dynamic models, we observe the behavior of the foreign exchange rate of a small open economy with rational expectation formation and different restrictions on the international economic integrations. First, an economy connected to the world by purchasing power parity and uncovered interest parity is studied in the next section. In both sections, financial assets available in the economy are domestic money and bonds. Stocks are added as a financial instrument in the next section, and real capital accumulation is also taken into account. Furthermore, the economy concerned there is fairly autonomous, and not directly governed by either purchasing power parity or uncovered interest parity. The expectation formation used throughout the whole paper is complete perfect foresight, which is the certainty version of rational expectation and free from any forecast errors. It is found that upon monetary expansion the short run depreciation of the foreign exchange rate is a fairly robust result regardless of the degree of the international economic integration, while it is not true for fiscal expansion. The expectation on the long run state significantly affects the short run response of the exchange rate. All of our models postulate that the current account should be balanced eventually. As the result, the short run behavior of the exchange rate is affected by the expectation on the long run balance and may well be a blend of the traditional flow view and modem asset view. The initial overshooting of the exchange rate is easily observed even in the fairly autonomous economy Furthermore, the initial overshooting is not reduced over time, but augmented for some time before it is eventually eliminated. As long as we maintain rational expectaion, introducing time delay in the adjustment of the foreign goods price to the foreign exchange rate does not make much difference.