Privacy Protection Method for Sensitive Weighted Edges in Social Networks

( Weihua Gong ),( Rong Jin ),( Yanjun Li ),( Lianghuai Yang ),( Jianping Mei ) 한국인터넷정보학회 2021 KSII Transactions on Internet and Information Syst Vol.15 No.2

Privacy vulnerability of social networks is one of the major concerns for social science research and business analysis. Most existing studies which mainly focus on un-weighted network graph, have designed various privacy models similar to k-anonymity to prevent data disclosure of vertex attributes or relationships, but they may be suffered from serious problems of huge information loss and significant modification of key properties of the network structure. Furthermore, there still lacks further considerations of privacy protection for important sensitive edges in weighted social networks. To address this problem, this paper proposes a privacy preserving method to protect sensitive weighted edges. Firstly, the sensitive edges are differentiated from weighted edges according to the edge betweenness centrality, which evaluates the importance of entities in social network. Then, the perturbation operations are used to preserve the privacy of weighted social network by adding some pseudo-edges or modifying specific edge weights, so that the bottleneck problem of information flow can be well resolved in key area of the social network. Experimental results show that the proposed method can not only effectively preserve the sensitive edges with lower computation cost, but also maintain the stability of the network structures. Further, the capability of defending against malicious attacks to important sensitive edges has been greatly improved.

Edge-Based Motion Vector Processing for Frame Interpolation Based on Weighted Vector Median Filter

PARK, Ju Hyun,KIM, Young-Chul,HOON, Hong-Sung The Institute of Electronics, Information and Comm 2010 IEICE transactions on information and systems Vol.93 No.11

<P>In this paper, we propose a new motion vector smoothing algorithm using weighted vector median filtering based on edge direction for frame interpolation. The proposed WVM (Weighted Vector Median) system adjusts the weighting values based on edge direction, which is derived from spatial coherence between the edge direction continuity of a moving object and motion vector (MV) reliability. The edge based weighting scheme removes the effect of outliers and irregular MVs from the MV smoothing process. Simulation results show that the proposed algorithm can correct wrong motion vectors and thus improve both the subjective and objective visual quality compared with conventional methods.</P>

A New Vertex-Coloring Edge-Weighting of Complete Graphs

Mohammad Reza Farahani 한국전산응용수학회 2014 Journal of applied mathematics & informatics Vol.32 No.1

Let G = (V E) be a simple undirected graph without loops and multiple edges, the vertex and edge sets of it are represented by V = V (G) and E = E(G), respectively. A weighting w of the edges of a graph G induces a coloring of the vertices of G where the color of vertex v, denoted Sv := Σ e∋v w(e). A k-edge-weighting of a graph G is an assignment of an integer weight, w(e) ∈{1, 2, ..., k} to each edge e, such that two vertex- color Sv Su be distinct for every edge uv. In this paper we determine an exact 3-edge-weighting of complete graphs k3q+1 ∀q ∈ N. Several open questions are also included.

A NEW VERTEX-COLORING EDGE-WEIGHTING OF COMPLETE GRAPHS

Farahani, Mohammad Reza The Korean Society for Computational and Applied M 2014 Journal of applied mathematics & informatics Vol.32 No.1

Let G = (V ; E) be a simple undirected graph without loops and multiple edges, the vertex and edge sets of it are represented by V = V (G) and E = E(G), respectively. A weighting w of the edges of a graph G induces a coloring of the vertices of G where the color of vertex v, denoted $S_v:={\Sigma}_{e{\ni}v}\;w(e)$. A k-edge-weighting of a graph G is an assignment of an integer weight, w(e) ${\in}${1,2,...,k} to each edge e, such that two vertex-color $S_v$, $S_u$ be distinct for every edge uv. In this paper we determine an exact 3-edge-weighting of complete graphs $k_{3q+1}\;{\forall}_q\;{\in}\;{\mathbb{N}}$. Several open questions are also included.

입지선정 범위 예측을 위한 신경망 기반의 엣지 가중치 예측

고정륜(JeongRyun Ko),전현주(Hyeon-Ju Jeon),전승훈(Joshua. Jeon),윤정섭(Jeong-seop Yoon),정재은(Jason J. Jung),김봉길(Bonggil Kim) 한국정보통신학회 2021 한국정보통신학회 종합학술대회 논문집 Vol.25 No.1

본 논문은 노드와 엣지로 이루어진 그래프 구성을 통해 신경망을 활용하여 엣지 가중치 예측 방안을 제안하고자 한다. 사회 구성요소 중 하나인 브랜드들의 중요도 높은 전략 중 출점전략에 대해 초점을 맞추어 보았다. 본 논문에서는 1) 브랜드 지점들을 노드로 구성하고, 지점 간 관계를 엣지로 구성한다. 그리고 지점 간 실제 도보 및 주행 가능 거릿값을 엣지 가중치로 표현한 그래프를 구성한다. 그리고 2)엣지를 수치화하여 신경망을 학습해 엣지의 가중치인 지점 간 거릿값을 예측하는 방안을 제안한다. 제안한 방식을 활용함으로 예측되는 특정 브랜드의 출점 범위를 성공적인 브랜드의 출점전략 분석할 시에 활용할 수 있을 것으로 예상한다. This paper is a proposal for edge weight prediction using neural networks to graph configurations of nodes and edges. Brand is one of the components of society. and one of the brand's most important strategies is geographical location strategy. This paper is focus on that strategy. In This paper propose two things: 1) Graph Configuration. node consists of brand store, edge consists of store-to-store relationships and edge weight consists of actual walk and drive distance values. 2) numbering edges and training neural networks to predict next store distance values. It is expected to be useful in analyzing successful brand geographical location strategies.

Image Restoration using Weighted Octagonal Median Filter

Eun-Kyung Lee,Cheol-Hun Na 한국정보통신학회 2021 2016 INTERNATIONAL CONFERENCE Vol.12 No.1

One of the most important tasks in image processing is noise filtering. Noise removal in image is a difficult task due to many reasons such as nonstationary sequences and corrupted by various types of noise. Human’s visual perception is heavily based on the edge information. Thus, noise filtering must preserve edges. To remove the noise, we usually use the square-shaped median filter. They possess mathematical simplicity but have the disadvantages that blur the edges. In this paper we consider a new technique for image restoration using a weighted octagonal median filter. This technique consists of simple hypothesis test for edge detection, and we use the weighted octagonal-shaped moving window. The new technique is applied to noise corrupted image and experimental results are compared to the results of the square-shaped median filter and the cross-shaped median filter.

Intensity-guided edge-preserving depth upsampling through weighted L₀ gradient minimization

Jung, Cheolkon,Yu, Shengtao,Kim, Joongkyu Elsevier 2017 Journal of visual communication and image represen Vol.42 No.-

<P><B>Abstract</B></P> <P>Depth is an important visual cue to perceive real-world scenes. Although a time-of-flight (ToF) depth camera can provide depth information in dynamic scenes, captured depth images are often noisy and of low resolution. In this paper, we propose an intensity-guided edge-preserving depth upsampling method through weighted L<SUB>0</SUB> gradient minimization to enhance both resolution and visual quality of depth images. Guided by the high-resolution intensity image, we perform optimization to preserve boundaries of objects. We apply L<SUB>0</SUB> gradient to the regularization term, and compute its weight from both intensity and depth images. We optimize the objective function using alternating minimization and half-quadratic splitting. Experimental results on Middlebury 2005, 2014, and real-world scene datasets demonstrate that the proposed method produces boundary-preserving depth upsampling results and outperforms state-of-the-art ones in terms of accuracy.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Intensity-guided edge-preserving depth upsampling. </LI> <LI> Weighted L<SUB>0</SUB> gradient minimization. </LI> <LI> Alternating minimization and half-quadratic splitting. </LI> <LI> Suppressing edge blurring and texture copying artifacts. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Fast Global Image Smoothing Based on Weighted Least Squares

Dongbo Min,Sunghwan Choi,Jiangbo Lu,Bumsub Ham,Kwanghoon Sohn,Do, Minh N. IEEE 2014 IEEE TRANSACTIONS ON IMAGE PROCESSING - Vol.23 No.12

<P>This paper presents an efficient technique for performing a spatially inhomogeneous edge-preserving image smoothing, called fast global smoother. Focusing on sparse Laplacian matrices consisting of a data term and a prior term (typically defined using four or eight neighbors for 2D image), our approach efficiently solves such global objective functions. In particular, we approximate the solution of the memory- and computation-intensive large linear system, defined over a d -dimensional spatial domain, by solving a sequence of 1D subsystems. Our separable implementation enables applying a linear-time tridiagonal matrix algorithm to solve d three-point Laplacian matrices iteratively. Our approach combines the best of two paradigms, i.e., efficient edge-preserving filters and optimization-based smoothing. Our method has a comparable runtime to the fast edge-preserving filters, but its global optimization formulation overcomes many limitations of the local filtering approaches. Our method also achieves high-quality results as the state-of-the-art optimization-based techniques, but runs ~10-30 times faster. Besides, considering the flexibility in defining an objective function, we further propose generalized fast algorithms that perform Lγ norm smoothing (0 <; γ <;2) and support an aggregated (robust) data term for handling imprecise data constraints. We demonstrate the effectiveness and efficiency of our techniques in a range of image processing and computer graphics applications.</P>

Absorption characteristics of nanoparticles with sharp edges for a direct-absorption solar collector

Qin, Caiyan,Kim, Joong Bae,Gonome, Hiroki,Lee, Bong Jae Elsevier 2020 RENEWABLE ENERGY Vol.145 No.-

<P><B>Abstract</B></P> <P>Plasmonic nanofluids has been reported beneficial for enhancing absorption of the solar energy in a direct-absorption solar collector (DASC). In order to overcome the shortage of narrow absorption band associated with the localized surface plasmon, two strategies can be adopted. One is to blend nanoparticles with different absorption peaks, and the other is to develop nanoparticles capable of exhibiting multiple absorption peaks at different wavelengths. In this study, the latter strategy is explored systematically by investigating the absorption efficiency of metallic nanoparticles with sharp edges. The results show that the Ag nanoparticles with sharp edges can induce multiple absorption peaks due to both localized surface plasmon resonance and lightning rod effect. We also show that the sharper edges (i.e., with either smaller radius of curvature or smaller edge angle) can greatly enhance the lightning rod effect. In addition, the study of SiO<SUB>2</SUB>-core/Ag-shell suggests that the core/shell configuration is beneficial for further broadening the absorption band compared to the Ag nanoparticle. Further investigation shows that the solar-weighted absorption coefficient of a DASC using the four-edge nanoparticle is 35% and 20% point higher than the nanosphere and the nanorod respectively with a fixed volume fraction of <SUP> 10 − 6 </SUP> .</P> <P><B>Highlights</B></P> <P> <UL> <LI> Ag nanoparticles with sharp edges can generate multiple absorption peaks. </LI> <LI> Multiple peaks are due to the localized surface plasmon and the lightning rod effect. </LI> <LI> More edges do not necessarily result in broader absorption. </LI> <LI> Core/shell nanoparticles exhibit broader absorption band than the Ag nanoparticles. </LI> <LI> Performance of a DASC with edged particles is much higher than smooth particles. </LI> </UL> </P>

가중 팔각형 메디안 필터를 이용한 영상 복원

이은영,나철훈,이은경 한국정보통신학회 2021 한국정보통신학회논문지 Vol.25 No.2

영상 처리에서 중요한 연구 분야 중 하나는 잡음 제거이다. 영상의 잡음 제거는 비정상 시퀀스 및 다양한 유형의 잡음에 의한 손상과 같은 여러 이유로 인해 해결하기 어려운 문제이기 때문이다. 인간의 시각적 인식은 에지 정보에 크게 의존한다. 따라서 잡음 제거 시 반드시 에지 정보를 보존해야 한다. 노이즈를 제거하기 위해 일반적으로 정방형 메디안필터를 사용한다. 이 방법은 수학적 단순성을 가지고 있지만 에지 영역을 흐리게 한다는 단점이 있다. 본 논문에서는 영상 내에 존재하는 잡음을 효과적으로 제거하기 위해서 에지 검출 알고리즘을 갖는 가중 팔각형 메디안 필터를 사용한 새로운 메디안 필터 윈도우를 제안하였다. 이 방법은 에지를 검출하기 위해 움직이는 가중 팔각형 창을 사용하였다. 그리고 결과를 일반 메디안 필터, 격자형 메디안 필터 그리고 본 논문에서 제안한 가중 팔각형 메디안 필터의 결과와 비교하였다. 실험 결과, 에지 검출 알고리즘을 갖는 가중 팔각형 메디안 필터를 이용한 영상 복원이 일반 메디안 필터나 격자형 메디안 필터를 사용한 결과보다 좋은 성능을 가짐을 확인하였다. One of the most important tasks in image processing is noise filtering. Noise removal in image is a difficult task due to many reasons such as nonstationary sequences and corrupted by various types of noise. Human’s visual perception is heavily based on the edge information. Thus, noise filtering must preserve edges. To remove the noise, we usually use the square-shaped median filter. They possess mathematical simplicity but have the disadvantages that blur the edges. In this paper we consider a new technique for image restoration using a weighted octagonal median filter. The technique consists of simple hypothesis test for edge detection, and we use the weighted octagonal-shaped moving window. The new technique is applied to noise corrupted image and experimental results are compared to the results of the square-shaped median filter and the cross-shaped median filter.