• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.9A
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• pp.697-703
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• 2009

Cognitive radios are typically known to exploit vacant spectrum resources in order not to interfere with primary communication systems. However, cognitive radios may not be able to secure a clear spectrum band in a bustling spectrum band. Underlay spectrum sharing provides a way to cope with such a spectrum sharing problem. Cognitive radios share the same spectrum band with the spectrum licensees, i.e., primary users, by adjusting signal transmission power so as not to severely deteriorate the performance of the primary users. We propose an underlay spectrum sharing policy leveraging uplink spectrum resource to be used in a cellular network. A pair of end terminals attempts to establish a direct point-to-point link, and perform as cognitive radios in the sense that they share the uplink radio resource of other primary users. We formulate the transmit power constraints of the cognitive radios and propose a practical uplink band sharing framework. Our simulation results demonstrate that such an uplink sharing underlay direct link can enhance the throughput performance of point-to-point link with low overhead.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.25 no.2
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• pp.97-104
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• 2016

In this study, the qualitative effects of the positional error of carrier pin holes on the planet load sharing characteristics of the three-point suspension gearbox of wind turbines were investigated experimentally. A 35-kW gearbox comprising two planetary gear stages and a parallel gear stage and size one-fourth of that of a 2-MW three-point suspension gearbox was used as the test gearbox. The strain gauges attached to the ring gear teeth of the input planetary gear stage were used for the purpose of this study. The applied loading conditions were 50%, 75%, and 100% of the rated torque, and the mesh load factor was used as the load sharing index. The experimental results indicated that both the magnitude and direction of the positional error of pin holes had a significant effect on the planet load sharing characteristics of the three-point suspension gearbox. In addition, an increase in the applied torque results in uniform load sharing.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.1C
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• pp.119-128
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• 2004

In this paper, a low-power 8-point DCT structure is proposed using add and shift operations. Proposed structure adopts 4 cycles for complete 8-point DCT in order to minimize size of hardware and to enable high-speed processing. In the structure, hardware for the first cycle can be shared in the next 3 cycles since all columns in the DCT coefficient matrix are common except sign. Conventional DCT structures implemented with only add and shift operation use CSD(Canonic Signed Digit) form coefficients to reduce the number of adders. To reduce the number of adders further, we propose a new structure using common sub-expression sharing techniques. With this techniques, the proposed 8-point DCT structure achieves 19.5% adder reduction comparison to the conventional structure using only CSD coefficient form.

• Proceedings of the IEEK Conference
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• 2003.07b
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• pp.1221-1224
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• 2003

A 64-point R2$^2$ SDF pipeline FFT processor using a new efficient computation sharing multiplier was designed. Computation sharing multiplication specifically targets computation re-use in multiplication of coefficient vector by scalar and is effectively used in DSP(Digital Signal Processing). To reduce the number of multipliers in FFT, we used the proposed computation sharing multiplier. The 64-point pipeline FFT processor was implemented by VHDL and synthesized using Max+PLUSII of Altera. The simulation result shows that the proposed computation sharing multiplier can be reduced to about 17.8% logic cells compared with a conventional multiplier. This processor can operate at 33MHz and calculate a 64-point pipeline FFT in 1.94 $mutextrm{s}$.

• Journal of Information Science Theory and Practice
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• v.5 no.3
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• pp.6-14
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• 2017

Workplace knowledge sharing is a complex process and there are a large number of studies in the area. In this article three theoretical approaches in library and information science are used to discuss knowledge sharing in the workplace. The approaches are information behavior, social capital, and information culture, and they bring important insights that need to be considered from a holistic management point of view when it comes to knowledge sharing. The individual's relation to different levels of context is important, meaning both in relation to work roles, work tasks, situations, organizational structures, and culture. The frameworks also shed light on where and how knowledge sharing activities are present in the organization. From a knowledge management point of view, it is important to acknowledge that when knowledge is valued, there is also an awareness of the knowledge sharing activities. Also, in addition to more traditional views of context, the frameworks bring forward different views on context, such as time and space as contextual factors.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.4
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• pp.1867-1875
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• 2011

In this paper, a low-area 256-point FFT structure is proposed. For low-area implementation CSD(Canonic Signed Digit) multiplier method is chosen. Because multiplication type should be less for efficient CSD multiplier application to the FFT structure, the Radix-$4^2$ algorithm is chosen for those purposes. After, in the proposed structure, the number of multiplication type is minimized in each multiplication block, the CSD multipliers are applied for implementation of multiplication. Furthermore, in CSD multiplier implementation, cell-area is more reduced through common sub-expression sharing(CSS). The Verilog-HDL coding result shows 29.9% cell area reduction in the complex multiplication part and 12.54% cell area reduction in overall 256-point FFT structure comparison with those of the conventional structure.

• Knowledge Management Research
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• v.17 no.1
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• pp.113-133
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• 2016

Why illegal digital contents sharing happens? This study pays attention to the fact that file sharing is an exchanging behavior between people and it is expanding despite of an illegal behavior and proposes that it is necessary for the phenomenon to be understood from social cultural point of view beyond a personal dimension. Based on the social exchange theory, this study demonstrates effects of file sharing attitudes and continuity, regarding 'group norm', 'popular demand', 'reciprocity' and 'social solidarity' as main factors. The main findings of this study are as followed;- First, it is shown that a tacit agreement of a group on file sharing is a determinant of positive attitude to file sharing and the intent of continual file sharing. Second, it is not found that the social relationship factors that are regarded as potential influential factors on file sharing attitude have effects on file sharing behavior, except for 'group norm'. Unlike previous studies, the results may come from the fact that this study deals with an illegal behavior. The third finding indicates a structural relationship between social relationship factors. When members of a group have more amicable attitude to file sharing including silence or a tacit agreement on file sharing, more people ask illegal sharing of files that they need. Such public demand creates expectation of reciprocity. As reciprocity maintains, social connectedness is strengthened. Then, strong social connectedness escalates the intent to maintain file sharing. It is important to notice that this study promotes understanding of how digital contents sharing happens by structuring and demonstrating influential relationship between characteristic factors of the social relationship.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.10a
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• pp.129-131
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• 2017

In the special situations such as the extension or construction of networks, network sharing can be a more favorable alternative. In this point, this research is to review the types and characteristics related to network sharing among mobile network operators(MNOs).

• Human Ecology Research
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• v.56 no.1
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• pp.99-108
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• 2018

This study develops a scale to measure the practice of consideration and sharing by adolescents. This data as an object of high school students in regards to items generated from the content validity test and preliminary study stage based on the consideration scale, literature review and expert for elementary school students on a 5-point Likert scale. The factor analysis of the collected data using SPSS 20.0 2 indicated the final fators. The three fanal factors designated by the measuring items are: 'practice of consideration and sharing', 'recognition of consideration and sharing', and 'self-recognition'. As a result of analyzing students' individual variables, this study found that family relationship satisfaction and school life satisfaction had positive relationship in self-recognition, recognition of consideration and sharing, practice of consideration and sharing, and total personality score. The measurement tools developed in this study, are expected to act as valid tools to develop a program that can increase the practice of consideration and sharing activities.

• ETRI Journal
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• v.32 no.1
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• pp.1-10
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• 2010

In this paper, we present a fast Fourier transform (FFT) processor with four parallel data paths for multiband orthogonal frequency-division multiplexing ultra-wideband systems. The proposed 128-point FFT processor employs both a modified radix-$2^4$ algorithm and a radix-$2^3$ algorithm to significantly reduce the numbers of complex constant multipliers and complex booth multipliers. It also employs substructure-sharing multiplication units instead of constant multipliers to efficiently conduct multiplication operations with only addition and shift operations. The proposed FFT processor is implemented and tested using 0.18 ${\mu}m$ CMOS technology with a supply voltage of 1.8 V. The hardware- efficient 128-point FFT processor with four data streams can support a data processing rate of up to 1 Gsample/s while consuming 112 mW. The implementation results show that the proposed 128-point mixed-radix FFT architecture significantly reduces the hardware cost and power consumption in comparison to existing 128-point FFT architectures.