• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.1
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• pp.1-19
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• 2015

With the recent popularity of smart terminals, the demand for high-data-rate transmission is growing rapidly, which brings a new challenge for the traditional cellular networks. Both device-to-device (D2D) communication and small cells are effective to improve the transmission efficiency of local communication. In this paper, we apply D2D communication into a small cell network system (SNets) and study about the optimization problem of resource allocation for D2D communication. The optimization problem includes system scheduling and resource allocation, which is exponentially complex and the optimal solution is infeasible to achieve. Therefore, in this paper, the optimization problem is decomposed into several smaller problems and a hierarchical scheme is proposed to obtain the solution. The proposed hierarchical scheme consists of three steps: D2D communication groups formation, the estimation of sub-channels needed by each D2D communication group and specific resource allocation. From numerical simulation results, we find that the proposed resource allocation scheme is effective in improving the spectral efficiency and reducing the outage probability of D2D communication.

• Bulletin of the Korean Mathematical Society
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• v.56 no.3
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• pp.649-658
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• 2019

In this paper, we prove some congruences involving the generalized Catalan numbers and harmonic numbers modulo $p^2$, one of which is $$\sum\limits_{k=1}^{p-1}k^2B_{p,k}B_{p,k-d}{\equiv}4(-1)^d\{{\frac{1}{3}}d(2d^2+1)(4pH_d-1)-p\({\frac{26}{9}}d^3+{\frac{4}{3}}d^2+{\frac{7}{9}}d+{\frac{1}{2}}\)\}\;(mod\;p^2)$$, where a prime number p > 3 and $1{\leq}d{\leq}p$.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.10
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• pp.168-176
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• 1996

This paper presetns a 2-D DCT architecture adopting accurac y compensator for reducing the hardware complexity and increasing processing speed in VL\ulcornerSI implementation. In the application fields such as moving pictures experts group (MPEG) and joint photographic experts group (JPEG), 2-D DCT processor must be implemented precisely enough to meet the accuracy specifications of the ITU-T H.261. Almost all of 2-D DCT processors have been implemented using many multiplications and accumulations of matrices and vectors. The number of multiplications and accumulations seriously influence on comlexity and speed of 20D DCT processor. In 2-D DCT with fixed-point calculations, the computation bit width must be sufficiently large for the above accuracy specifications. It makes the reduction of hardware complexity hard. This paper proposes the accuracy compensator which compensates the accuracy of the finite word length calculation. 2-D DCT processor with the proposed accuracy compensator shows fairly reduced hardware complexity and improved processing speed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.10
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• pp.601-609
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• 2014

This paper proposes a resource allocation scheme suitable for D2D communications in multi-cell environment. In order to solve the inter-cell interference, the proposed scheme allocates the pre-assigned resource group and shares the information with neighbor cells. This paper also proposes a power control scheme for D2D communication to enhance the cell throughput. By the simulation results, the average SINR of the cellular uplink and D2D communication link are mostly higher than 10 dB when the proposed scheme is applied. On the other hand, with the inter-cell non-coordinated resource allocation scheme, the average SINR of the D2D communication link are decreased by 0 dB. In addition, the proposed scheme can enhance the cell throughput up to 8 % compared with the inter-cell non-coordinated resource allocation scheme.

• International Journal of Computer Science & Network Security
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• v.21 no.1
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• pp.152-161
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• 2021

The paper focuses on Device-to-device (D2D) Architectures evaluation frameworks. D2D communication and discovery can improve spectrum usage efficiency and optimize the tradeoffs between throughput and energy consumption. The target operation modes involve both indirect communication between two nodes via a base station or the direct communication among proximal nodes, enabling use cases that can support communications out of cellular coverage, as well as low end-end delay requirements. The paper will present the architectural evolution of D2D networks within 3GPP standardization and will highlight key network functionalities and signaling protocols. It will also identify key analytical and simulation models that can be used to assess the performance and energy efficiency of resource allocation strategies, and it will present a suitable cross-layer integrated framework.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.10
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• pp.1881-1886
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• 2016

In this paper, by using D2D communications that perform direct communications among devices within small transmission range of each device without base station, we assume that a device generates and transmits data packets to other proximate devices and the devices which receive the data packets relay those to other adjacent devices. To maximize the total number of devices which successfully receive data packets, Epidemic routing protocol is considered in this paper. In Epidemic routing protocol, all devices which received data packets try to relay the packets to other adjacent devices. We assume various network environment where devices are densely distributed in specific area(crowded area). In this environment, D2D SD can be a source node and D2D devices can be relay nodes. By setting transmission range of D2D SD and D2D devices as parameters, we analyze performance results of coverage probability of Epidemic routing protocol through intensive simulations.

• Journal of the Korea Society of Computer and Information
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• v.23 no.8
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• pp.25-30
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• 2018

In this paper, we design a 2D one touch runner game which controls on smart device easily using a Unity3D game engine. Unity is the creator of the world's widely-used 2D and the 3D cross-platform game engine developed by Unity Technologies. Also, Unity builds high-quality 2D and 3D games on a various hardware device. This paper shows the familiar character as a cartoon and feels to enjoy using platformer with various game users. we show that the proposed platformer method improve controlling game path on the smart device.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.4
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• pp.1897-1903
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• 2011

This paper discusses a 2D/3D conversion of images using technologies like object extraction and depth-map creation. The general procedure for converting 2D images into a 3D image is extracting objects from 2D image, recognizing the distance of each points, generating the 3D image and correcting the image to generate with less noise. This paper proposes modified new methods creating a depth-map from 2D image and recognizing the distance of objects in it. Depth-map information which determines the distance of objects is the key data creating a 3D image from 2D images. To get more accurate depth-map data, noise filtering is applied to the optical flow. With the proposed method, better depth-map information is calculated and better 3D image is constructed.

• Journal of the Korean housing association
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• v.17 no.5
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• pp.47-54
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• 2006

This study aims to evaluate the sound insulation performance of Korean traditional paper(Hanji) windows as a material of environmental friendly building. Six types of traditional windows with 4 types of traditional window positions, were installed in l/2.5 scale model house. And then according to KS F 2235, comparative sound level differences between outdoor and indoor were measured. The main results are as follows; 1) TL(Transmission Loss) of Korean traditional paper windows, which cover one eighth of total balcony window, are ranged from 15 to 19 dB(A) in the living room and from 8 to 11 dB(A) in the balcony space. 2) TL of Korean traditional paper windows, which cover one fourth of total balcony window, are ranged from 10 to 19 dB(A) in the living room and from 8 to 10 dB(A) in the balcony space. 3) TL of Korean traditional windows with one side-one layer paper is ranged from 10 to 21 dB(A) and two side-one layer paper is 15 to 23 dB(A) and two side-two layer paper is 19 to 23 dB(A) respectively.

• Speech Sciences
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• v.2
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• pp.45-55
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• 1997

This paper describes the procedure of implementing an articulatory speech simulator, in order to model the human articulatory organs and to synthesize speech from this model after. Images required to construct the vocal tract model were obtained from MRI, they were then used to construct 2D and 3D vocal tract shapes. In this paper 3D vocal tract shapes were constructed by spatially concatenating and interpolating sectional MRI images. 2D vocal tract shapes were constructed and analyzed automatically into a digital filter model. Following this speech sounds corresponding to the model were then synthesized from the filter. All procedures in this study were using MATLAB.