• Journal of Korea Multimedia Society
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• v.14 no.10
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• pp.1238-1242
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• 2011

An efficient architecture for the reduction of complexity in forward quantization of H.264/AVC is presented in this paper. Since the multiplication operation in forward quantization plays crucial role in complexity of algorithm. More efficient quantization architecture with simplified high speed multiplier is proposed. It uses the modification of the quantization operation and the high speed multiplier is applied for simplification of quantization process.

• JSTS:Journal of Semiconductor Technology and Science
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• v.17 no.1
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• pp.101-109
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• 2017

This paper presents a high-throughput low-complexity 512-point eight-parallel mixed-radix multipath delay feedback (MDF) fast Fourier transform (FFT) processor architecture for orthogonal frequency division multiplexing (OFDM) applications. To decrease the number of twiddle factor (TF) multiplications, a mixed-radix $2^4/2^3$ FFT algorithm is adopted. Moreover, a dual-path shared canonical signed digit (CSD) complex constant multiplier using a multi-layer scheme is proposed for reducing the hardware complexity of the TF multiplication. The proposed FFT processor is implemented using TSMC 90-nm CMOS technology. The synthesis results demonstrate that the proposed FFT processor can lead to a 16% reduction in hardware complexity and higher throughput compared to conventional architectures.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.2A
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• pp.100-107
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• 2011

Algorithms based on the QR decomposition of the equivalent space-time channel matrix have been proved useful in the detection of V-BLAST systems. Especially, the parallel detection (PD) algorithm offers ML approaching performance up to 4 transmit antennas with reasonable complexity. We show that when directly applied to STBCs, the PD algorithm may suffer a rather significant SNR degradation over ML detection, especially at high SNRs. However, simply extending the PD algorithm to allow p ${\geq}$ 2 candidate layers, i.e. p-PD, regains almost all the loss but only at a significant increase in complexity. Here, we propose a simplification to the p-PD algorithm specific to STBCs without a corresponding sacrifice in performance. The proposed algorithm results in significant complexity reductions for moderate to high order modulations.

• JSTS:Journal of Semiconductor Technology and Science
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• v.16 no.4
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• pp.488-496
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• 2016

This paper presents a low-complexity non-iterative soft-decision Bose-Chaudhuri-Hocquenghem (SD-BCH) decoder architecture and design technique for wireless body area networks (WBANs). A SD-BCH decoder with test syndrome computation, a syndrome calculator, Chien search and metric check, and error location decision is proposed. The proposed SD-BCH decoder not only uses test syndromes, but also does not have an iteration process. The proposed SD-BCH decoder provides a 0.75~1 dB coding gain compared to a hard-decision BCH (HD-BCH) decoder, and almost similar coding gain compared to a conventional SD-BCH decoder. The proposed SD-BCH (63, 51) decoder was designed and implemented using 90-nm CMOS standard cell technology. Synthesis results show that the proposed non-iterative SD-BCH decoder using a serial structure can lead to a 75% reduction in hardware complexity and a clock speed 3.8 times faster than a conventional SD-BCH decoder.

• Management Science and Financial Engineering
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• v.4 no.2
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• pp.1-13
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• 1998

The Shortest Path Problem in Time-dependent Networks, where the travel time of each link depends on the time interval, is not realistic since the model and its solution violate the Non-passing Property (NPP:often referred to as FIFO) of real phenomena. Furthermore, solving the problem needs much more computational and memory complexity than the general shortest path problem. A new model for Time-dependent Networks where the flow speeds of each link depend on time interval, is suggested. The model is more realistic since its solution maintains the NPP. Solving the problem needs just a little more computational complexity, and the same memory complexity, as the general shortest path problem. A solution algorithm modified from Dijkstra's label setting algorithm is presented. We extend this model to the problem of Minimum Expected Time Path in Time-dependent Stochastic Networks where flow speeds of each link change statistically on each time interval. A solution method using the Kth-shortest Path algorithm is presented.

• Management Science and Financial Engineering
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• v.10 no.1
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• pp.1-23
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• 2004

The changing structure of organization and the increasing diversity of business have forced organizations to have abilities to coordinate dispersed business activities. They have required cooperation and coordination among the functional units in the organization which should involve group decision-making processes. Although many group decision-making support tools and methods have been introduced to enable the collaborative process of group decision-making, they often lack the features supporting the dynamic complexity issue frequently occurring at group decision-making processes. This results in cognitive unfit between the group decision-making tasks and their supporting tools, bringing about mixed results in their effects on group decision-making. This study proposes system dynamics modeling as a group decision-making support tool to deal with the group decision -making tasks having properties of dynamic complexity in terms of cognitive fit theory.

• Journal of the Korean Operations Research and Management Science Society
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• v.28 no.4
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• pp.31-37
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• 2003

This paper deals with a stowage plan for plates in a warehouse. This plan includes how to place each plate and how to sequence outgoing lots for picking. A group of plates in an outgoing lot should be loaded in the same outgoing pallet and between two elates in the same lot, no plate from other than the lot should be placed. Since the approach to the plates is only from above, when the plates in the different lots are placed mixed in a warehouse, we have to temporarily move many of plates in some other place to let a plate in the lot for which loading is under way go out. Our purpose is to minimize those temporary moves. We analyze the computational complexity of several problems arising in the stowage plan of a plate warehouse.

• ETRI Journal
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• v.34 no.4
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• pp.503-510
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• 2012

We analyze the relationship between channel coherence bandwidth and two complexity-reduced lattice reduction aided detection (LRAD) algorithms for multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) systems in correlated fading channels. In both the adaptive LR algorithm and the fixed interval LR algorithm, we exploit the inherent feature of unimodular transformation matrix P that remains the same for the adjacent highly correlated subcarriers. Complexity simulations demonstrate that the adaptive LR algorithm could eliminate up to approximately 90 percent of the multiplications and 95 percent of the divisions of the brute-force LR algorithm with large coherence bandwidth. The results also show that the adaptive algorithm with both optimum and globally suboptimum initial interval settings could significantly reduce the LR complexity, compared with the brute-force LR and fixed interval LR algorithms, while maintaining the system performance.

• Management Science and Financial Engineering
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• v.20 no.2
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• pp.7-12
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• 2014

Content Delivery Network (CDN) has evolved to overcome a network bottleneck and improve user perceived Quality of Service (QoS). A CDN replicates contents from the origin server to replica servers to reduce the overload of the origin server. CDN providers would try to achieve an acceptable performance at the least cost including the storage space or processing power. In this paper, we introduce a new optimization model for the CDN design problem considering the user perceived QoS and single path (non-bifurcated) routing constraints and analyze the computational complexity for some special cases.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.405-409
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• 2007

Each class in remotely sensed imagery has different spectral and spatial characteristics. Natural features have relatively smaller spatial changes than spectral changes. Meanwhile, urban area in which buildings, roads, and cars are included is inclined to face more changes of spatial variation than spectral one. This study aims to propose the new urban complexity index (UCI) based on the 3D DWT computation of remotely sensed imageries considering these characteristics. And then we analyze relation between index and land cover map. The 3DWUCI values are related to class and the indices of urban area are greater than natural area. The proposed UCI could be used to express effectively the standard of urban complexity over a wide area.