• JSTS:Journal of Semiconductor Technology and Science
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• v.14 no.4
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• pp.419-426
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• 2014

This paper proposes a high-throughput encoding process and encoder architecture for quasi-cyclic low-density parity-check codes in IEEE 802.11ac standard. In order to achieve the high throughput with low complexity, a partially parallel processing based encoding process and encoder architecture are proposed. Forward and backward accumulations are performed in one clock cycle to increase the encoding throughput. A low complexity cyclic shifter is also proposed to minimize the hardware overhead of combinational logic in the encoder architecture. In IEEE 802.11ac systems, the proposed encoder is rate compatible to support various code rates and codeword block lengths. The proposed encoder is implemented with 130-nm CMOS technology. For (1944, 1620) irregular code, 7.7 Gbps throughput is achieved at 100 MHz clock frequency. The gate count of the proposed encoder core is about 96 K.

• The Transactions of the Korea Information Processing Society
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• v.2 no.3
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• pp.314-323
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• 1995

Recently, as users' understanding about software is raised, software developers devoted all their energy to satisfy users' needs. Accordingly, software is getting increase in volume and becoming complicated. As account of it, development and maintenance costs of software have been increased, and a large number of developers were projected in maintenance and development of new software. Software with good maintenability has a function in a module and is easy to read and simple. In this paper, for effective management of software complexity, I designed and implemented the system which accepts source program by input and measures product metrics and produce measurement value of factor items.

• ETRI Journal
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• v.38 no.1
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• pp.100-111
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• 2016

This paper presents a low-complexity channel-adaptive reconfigurable $4{\times}4$ QR-decomposition and M-algorithm-based maximum likelihood detection (QRM-MLD) multiple-input and multiple-output (MIMO) detector. Two novel design approaches for low-power QRM-MLD hardware are proposed in this work. First, an approximate survivor metric (ASM) generation technique is presented to achieve considerable computational complexity reduction with minor BER degradation. A reconfigurable QRM-MLD MIMO detector (where the M-value represents the number of survival branches in a stage) for dynamically adapting to time-varying channels is also proposed in this work. The proposed reconfigurable QRM-MLD MIMO detector is implemented using a Samsung 65 nm CMOS process. The experimental results show that our ASM-based QRM-MLD MIMO detector shows a maximum throughput of 288 Mbps with a normalized power efficiency of 10.18 Mbps/mW in the case of $4{\times}4$ MIMO with 64-QAM. Under time-varying channel conditions, the proposed reconfigurable MIMO detector also achieves average power savings of up to 35% while maintaining a required BER performance.

• International Journal of Naval Architecture and Ocean Engineering
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• v.4 no.3
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• pp.291-301
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• 2012

A scalar metric for the assessment of hull surface producibility was known to be useful in estimating the complexity of a hull form of ships or large offshore structures by looking at their shape. However, it could not serve as a comprehensive measuring tool due to its lack of important components of the hull form such as longitudinals, stiffeners, and web frames attached to the hull surface. To have a complete metric for cost estimation, these structural members must be included. In this paper, major inner structural members are considered by measuring the complexity of their geometric shape. The final scalar metric thus consists of the classes containing inner members with various curvature magnitudes as well as the classes containing curved plates with single and double curvature distribution. Those two distinct metrics are merged into a complete scalar metric that accounts for the total cost estimation of complex structural bodies.

• Journal of Communications and Networks
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• v.18 no.1
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• pp.84-94
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• 2016

Design of effective cooperative jamming (CJ) algorithm is studied in this paper to maximize the achievable secrecy rate when the total transmit power of the source and multiple trusted terminals is constrained. Recently, the same problem was studied in [1] and an optimal algorithm was proposed involving a one-dimensional exhaustive searching.However, the computational complexity of such exhaustive searching could be very high, which may limit the practical use of the optimal algorithm. We propose an asymptotically optimal algorithm, involving only a fast line searching, which can guarantee to achieve the global optimality when the total transmit power goes to infinity. Numerical results demonstrate that the proposed asymptotically optimal algorithm essentially gives the same performance as the algorithm in [1, (44)] but with much lower computational complexity.

• Journal of Information Technology Services
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• v.9 no.4
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• pp.219-229
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• 2010

The Green's equivalence relations have played a fundamental role in the development of semigroup theory. They are concerned with mutual divisibility of various kinds, and all of them reduce to the universal equivalence in a group. Boolean matrices have been successfully used in various areas, and many researches have been performed on them. Studying Green's relations on a monoid of boolean matrices will reveal important characteristics about boolean matrices, which may be useful in diverse applications. Although there are known algorithms that can compute Green relations, most of them are concerned with finding one equivalence class in a specific Green's relation and only a few algorithms have been appeared quite recently to deal with the problem of finding the whole D or J equivalence relations on the monoid of all $n{\times}n$ Boolean matrices. However, their results are far from satisfaction since their computational complexity is exponential-their computation requires multiplication of three Boolean matrices for each of all possible triples of $n{\times}n$ Boolean matrices and the size of the monoid of all $n{\times}n$ Boolean matrices grows exponentially as n increases. As an effort to reduce the execution time, this paper shows an isomorphism between the R relation and L relation on the monoid of all $n{\times}n$ Boolean matrices in terms of transposition. introduces theorems based on it discusses an improved algorithm for the J relation computation whose design reflects those theorems and gives its execution results.

• Journal of the Semiconductor & Display Technology
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• v.20 no.3
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• pp.71-76
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• 2021

Digital decimation filters are used in various digital signal processing systems using ADCs, including digital communication systems and sensor network systems. When the sampling rate of digital data is reduced, aliasing occurs. So, an anti-aliasing filter is necessary to suppress aliasing before down-sampling the data. Since the anti-aliasing filter has to have a sharp transition band between the passband and the stopband, the order of the filter is very high. However, as the order of the filter increases, the complexity and area of the filter increase, and more power is consumed. Therefore, in this paper, we propose two types of decimation filters, focusing on reducing the area of the hardware. In both cases, the complexity of the circuit is reduced by applying the required down-sampling rate in two times instead of at once. In addition, CIC decimation filters without a multiplier are used as the decimation filter of the first stage. The second stage is implemented using a CIC filter and a down sampler with an anti-aliasing filter, respectively. It is designed with Verilog-HDL and its function and implementation are validated using ModelSim and Quartus, respectively.

• Journal of Distribution Science
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• v.19 no.7
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• pp.61-73
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• 2021

Purpose: This study offers suggestions to e-commerce companies for increasing shoppers' repurchase intention by considering the effect of distribution information in online shopping. It applies complexity theory to incorporate habitual information search behavior and shopper characteristics into the Stimulus-Organism-Response model and indicates how these complex factors work together in online shopping. Research design, data, and methodology: This study used an interview survey of 158 Vietnamese consumers with an experience of online shopping. A fuzzy-set Qualitative Comparative Analysis (fsQCA) was used to examine the relationship between antecedents and outcomes depending on complex conditions in the given contexts. Results: The results (1) indicate the importance of observing information search patterns and investigating their influence on online distribution, and (2) clarify what kind of configurations, under what conditions, predict a high or low outcome; this provides evidence and hints for the development of frameworks for future studies. Conclusions: The findings suggest that shoppers' unconscious, habitual behavior can work with conscious attitude factors, such as satisfaction, to increase their repurchase intention. Hence, e-commerce companies should consider how to present useful distribution information and create functions that allow shoppers to engage with a variety of information while increasing their repurchase intention on the site.

• Journal of Distribution Science
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• v.20 no.8
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• pp.33-46
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• 2022

Purpose: This study aims to understand the impact of e-commerce's advantage among SME's digital channel in Malaysia. To achieve the objective, this study used Technology, Organization, Environment (TOE) framework, Diffusion of Innovation (DOI) theory and Resource-Based View (RBV) theory. Research design, data and methodology: This study is quantitative method involve 195 SMEs online business in Malaysia. The integrated framework highlights the conceptual insight in multidimensional technology context (i.e. relative advantage, compatibility, and complexity); organizational context (i.e. top management support, innovation capability, branding capability, market-sensing capability, and human and organization capability); and environmental context (i.e. government support and supplier pressure). Results: The findings revealed that complexity, branding capability, human and organization capability, government support, and supplier pressure have significant positive relationship with e-commerce advantage. Meanwhile, relative advantage, compatibility, innovation capability, and market-sensing capability have significant negative relationship with e-commerce advantage. However, top management support has found no significant relationship with e-commerce advantage. Conclusions: The extended theoretical framework dimension improves existing knowledge on e-commerce advantage as well as the prospect of SMEs digital channel.

• Journal of Korea Trade
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• v.26 no.8
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• pp.58-76
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• 2022

Purpose - This study examined the Rules of Origin (RoO) as a factor affecting free trade agreements' (FTA) utilization and analyzed the causal relationship and the effects of these factors on the export performance of automobile parts companies. Design/methodology - We analyzed and verified the impact of FTA utilization and the export performance of automobile parts companies by dividing the characteristics of the RoO into complexity and uncertainty. Following which, various statistical analyses were conducted on the interrelationships among these variables. Findings - This research analyzed the effect of the RoO factors of complexity and uncertainty on the use of FTA and the export performance of automobile parts companies. We found that these characteristics of RoO were generally related to and affected the FTA use and export performance of these companies. Based on this, this study's investigation into the characteristics of the RoO would then help companies in better utilizing the FTA, as well as providing suggestions on how to effectively respond to the application of the FTA in the future. Originality/value - Companies that want to utilize FTAs in international trade must follow the RoO. In the Regional Trade Agreement (RTA), the country-of-origin is a key factor, with the RoO being an important requirement for the application of preferential tariffs. These regulations are a requirement for receiving FTA preferential treatment; however, they also cause difficulties to companies in using the FTA.