Studies in System Science (SSS) Volume 3, 2015
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Analysis of Product Quality and Safety Information Transmission Characteristics of News Website Based on Complex Network Zhuohui Liu1, Yuexiang Yang2, Tiyan Xiang*3, Bo Xu4 China Society of Inspection and Quarantine, Beijing, China
1
China National Institute of Standardization, Beijing, China
2
Information Department,China Academic Degrees and Graduate Education Development Center, BeiJing, China
3
School of Economics and Management, Beihang University, Beijing, China
4
liuzhuohui@aqsiq.gov.cn; 2yangyx@cnis.gov.cn; *3xiangbhtina@sina.com; 4xb39082119@163.com
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Abstract The paper uses the complex network theory to analyze the source channels, transmission characteristics and influence factors of the quality and safety information in news websites. With the analysis of statistical indexes in complex network such as degree and path, we find the static topology characteristics in the process of product quality and safety information transmission. We also analyze the specific factors that influence the dynamic evolution of product quality and safety information transmission network from overall network characteristic, local network characteristic and evolution time. The deep analysis of the characteristics of product quality and safety information transmission is beneficial to building the product quality and safety information transmission model and prediction model. It’s significant in building and improving the risk monitoring system of product quality and safety and evading the harm brought by product quality and safety problem effectively. Keywords Product Quality and Safety; Information Transmission; Complex Network; News Websites
Introduction In recent years, with the fast and constant improvement of science and technology, product quality and safety has become the focus of attention and public opinion. Product quality and safety is not only related to the health and safety of most people, but also the healthy development of national economy and social harmony and stability. When product quality and safety problems occur, the related information will be transmitted on the Internet through forum, website, blog, micro-blog, instant messaging tools with tremendous speed. The Internet news site is the main medium for product quality and safety information transmission. The Internet news site means the Internet website built by news units and its information transmission has the characteristics of wide source, fast transmission speed and broad scope of influence. The information is easily discussed in the socialized media. The deep discussion and research of the transmission channel, process, characteristics and influence factors of product quality and safety information in news websites is beneficial to mastering the transmission law of quality and safety information, building and improving the risk monitoring system of product quality and safety. It’s significant in effectively evading the harm brought by product quality and safety problem and securing the safe operation of national economy and social stability. Complex Network Theory The research of complex network is permeating many different fields such as mathematics, life science and social science. The scientific understanding of the quantitative and qualitative characteristics of complex network has become an important and challenging subject of the scientific research in the network era. Complex Network means the network which has self-organizing, self-similar, attractor, and small world, without part or
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the whole features of degree. The complexity of complex network is mainly in structural complexity, network evolution, connection diversity, dynamic complexity, node diversity, multiple complexities [1]. In the field of natural science, the basic measures of complex network research include: degree and its distribution characteristics, relativity of degree, agglomeration degree and its distribution characteristics, the shortest distance and its distribution characteristics, betweenness and its distribution characteristics. At present, there are many scholars who research and discuss the transmission law of Internet information with complex network theory. Yang Bo systematically analyzed the existence and its characteristics of group structure in the public opinion transmission network [2]; Tong Yala analyzed the evolution mechanism of public opinion information transmission of mass unexpected incidents and deeply discusses the prediction model of public opinion information flow[3]; Tian Zhanwei made the example analysis of the information transmission characteristics of micro-blog and he found out its characteristics of cluster line, small world and highly centralization[4]. However, there are few researches of analyzing the product quality and safety information transmission characteristics using complex network. The network can be described as a figure G(V,E) which is made up of point set V and side set E. We bring the knowledge of graph theory into the research of complex network and complex network consists of nodes and sides. In the product quality and safety information transmission network, news website is different from traditional media. Many contents are not original and the contents are reprinted by news websites. With the reprinting relationship, we can know the news source, the chronological sequence of publishing and the path of information transmission. The mutual reprinting of news websites constitutes the complex news transmission relationship and it shows some of the characteristics of complex network, such as highly local cohesiveness, small world, core-edge feature. Introducing the network theory into the field of product quality and safety information transmission is beneficial to the discovery from the angle of network transmission structure and the prediction of information transmission process. Analysis of Information Source Channel The paper used Baidu news search engine as the research object to analyze the source channel and mutual reprinting relationship of product quality and safety information. The paper used more than 50 product quality safety events from Feb. 1, 2014 to Aug. 1, 2014, such as “honey fraud”, “formaldehyde standard of red scarf”, “Wanke poisonous floor”, “cancer caused by CROCS”, “formaldehyde standard of summer sleeping mat”, “repellent floral water with insecticide”, “glow stick quality safety”, “stroller textile net lead exceeding standard”. There are 25170 news data. We analyze the news title, release time, news source and abstract. Seeing from the report number of different source channels, the report numbers of the main information source channels are: ① newspaper, magazine and periodical account for 46%; ② TV accounts for 1.2%; ③ microblog accounts for 1.5%; ④ website account for 51.3%. News website and traditional website are the main sources of product quality and safety information, 685 news websites are involved. The reprinting number of different news sources is quite different. The top 10 news sources are Xinhua Net, China News Website, National Business Daily, Beijing News, Chinese Radio Network, people.com.cn, China Business News, STCN, Beijing Daily, China Economic Net, the related news being reprinted is 1530 which account for 33.2% of the total news source. The least 200 news source being reprinted is reprinted 260 times in total which account no more than 6% of the total number of being reprinted. It shows that web portals tend to reprint the high-profile websites and the same news of some high-profile website may be reprinted by different web portals. The number of being reprinted in the socialized media such as micro-blog and forum is little. Web portals rarely quote the content in micro-blog and forum to release news. It shows that the horizontal transmission from socialized media to traditional news website is little. We take the news websites involved as the node and the reprinting relationship between news websites as the arc to build the complex network of product quality and safety information transmission. According to the statistical data, the complex network is the weakly-connected directed network which has 25170 arcs. It can be shown as a 685 × 685 adjacent matrix.
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0 a 2,1 N = ... a685,1
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a1,2 0 ... a685,2
... a1,685 ... a2,685 ... ... ... 0
ai , j (I, j=1, 2…685) is the relationship between i node news website and j node news website. a i , j = 0 is that whether there is news reprinting between i node and j node. a i , j = 1 is that there is news reprinting between i node and j node. We use the Pajek software to draw the network diagram between 685 news nodes and the network structure is shown in Fig. 1. Green is the original news node and red is the reprinted news node. When the node is both original news node and reprinted news node, it’s treated as original news.
FIG. 1 THE NETWORK CONSTITUTED BY PART OF THE NODES IN PRODUCT QUALITY AND SAFETY INFORMATION NETWORK
Analysis of Static Topology Characteristics According to the research content, we analyze the degree and path of complex network. The Structural Analysis Based on the Statistical Characteristic Index of Degree We analyze the connection characteristics between nodes of product quality and safety information network from two indexes of degree value and cluster, and the distribution of community and the connection characteristics of communities. 1) Degree value analysis Degree is the number of the sides connecting the nodes. As the side of product quality and safety information network is a directed side, also called arc, the degree of network can be divided into Out degree and In degree. Out degree is the number of news nodes which the news of the node being reprinted. In degree is the number of news nodes which the node reprints other news nodes. Out and In degree can reflect the news a news website reprint other news and the news being reprinted. The greater the Out degree is, the larger the number of news being reprinted. The greater the In degree is, the larger the number of news reprinted from other news websites. The related data of node degree in product quality and safety information network is shown in Fig. 1.
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TABLE 1 NODE DEGREE OF PRODUCT QUALITY AND SAFETY INFORMATION NETWORK
Index
Out degree
In degree
Minimum value
0
0
Maximum value
198
382
Mean value
3.9
3.9
Median value
1.8
2.6
Mode
0
2
The data shows that the top 20% nodes being reprinted in the complex network of product quality and safety information transmission account for 82.4% of the total number of news being reprinted; in the website nodes whose number of news being reprinted rank the top 20%, the number of news being reprinted is 85.4% of the total number of news being reprinted. It shows the contribution of a few famous nodes to information transmission. It shows the similar law to that of “80/20” and it explains the importance of a few nodes. 2) Cluster Cluster is the possibility degree of adjacent nodes, which is the cluster degree of network connection. Cluster coefficient Ci is usually used to reflect the cluster degree. In the undirected network, and the weight of a side isn’t considered, then the cluster coefficient of single node is defined as:
Ci =
2li ki (ki − 1)
In the formula, li is the number of sides connected to i node; ki is the number of nodes which has the connection relationship with i node [5]. As the product quality and safety information network is a directed network, we can do the special treatment to the network. We can take all the directed arcs as sides and replace the situation of several connected lines between nodes with single side. The undirected network after treatment uses the above formula to calculate and the cluster coefficient of product quality and safety information network using Pajek is 0.005487. It’s several orders of magntiude greater than the random network cluster coefficient of the same size. It shows that product quality and safety information network is a typical small-world network. The network consists of many small networks connected to each other. There is mutual connection between networks and they constitute the variously connected complex network. The Analysis Based on the Statistical Characteristic Index of Path We analyze the network weakness and efficiency of information transmission in the complex network of product quality and safety information transmission from the indexes of average distance, diameter, centrality and centralization. 1) Average distance and diameter The side of the shortest path between two nodes of i and j in all the paths is called the distance of node
di , j . The
longest side of any of the two nodes of i and j is D. The average value of the distance between two nodes is the average path distance of network L.
= l
1 = ∑ di, j (i, j 1, 2,..., N ) N ( N − 1) i ≠ j
N is the number of network nodes. In the relationship network of news transmission network node, D is the longest distance between two nodes and L is the average number of nodes connecting the shortest relationship chain of two nodes in the network. Through the calculation with Pajek, we can get the longest distance of product quality and safety information network D=6 and the average path distance L=2.85. It shows the
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characteristics of small world. 2) Centrality and centralization Centrality is one of the important indexes of evaluating the influence of node in the network. Centralization is the relative capacity of network node as the network center. The node with greater centralization is more likely to be the center of network. The largest Out degree of all the nodes in product quality and safety information network is 198 and it comes from China News. 28.9% of the nodes in the network are related to the node. It shows that the information it sends can be browsed or searched by these nodes. The information is widely spread through these nodes in a short time. As the best get selected, the other nodes in the network will connect the node on its own initiative. In comparison with other nodes in the network, the node with the largest centralization has high degree of attention and this node has a relatively important position in the network. The other evaluation index to evaluate the transmission capacity of a node is betweenness centrality. We take the node which has the largest number of transmission and the most the shortest path passing through as the center of the network. We use the ratio that the number of the shortest paths passing through the node and the total number of network sides to describe the betweenness centrality Cb ( a ) of a node, and the formula is:
Cb (a ) = In the formula,
2∑ g jk (a ) j <k
(n − 1)(n − 2) g jk
g jk is the number of the shortest distances of node i and j; g jk (a ) is the number of shortest
distances of node i and j passing through node a. As the number of nodes is large in the complex network of product quality and safety information transmission, the value of betweenness centrality will be a small value. But there is a big difference in the value of betweenness centrality between nodes. Then the position of center point is prominent. After calculation, we found the betweenness centrality which is smaller than 0.008 in the network accounts for 99.97% in the total number of nodes. The degree value of the node with the biggest betweenness centrality is the second biggest node. Obviously, the betweenness centrality with bigger degree value tends to be bigger, the sharing efficiency of information transmission is higher and the transmission efficiency is better when the information passes through the node. The centralization degree of network
CNg is shown as: C = g N
In the formula,
∑ (C
x∈N
* N
− CN (a ))
(n − 1) max(CN* − CN (a ))
CN* is the biggest value of network centralization. If CNg is 1, it means the star chart with the
highest degree of centralization; if
CNg is 0, it means the degree of centralization of each node stays the same.
After calculation, the In degree centralization of complex network of product quality and safety information transmission is 0.92 and the value of betweenness centrality is 0.97. It means the network has good centralization and it shows strong centralization. It provides the evidence for the statement of controlling nodes to influence information transmission. It’s feasible to influence the transmission act of information through different control strategies and its feasibility is supported by data. Dynamic Evolution Analysis The evolution process of product quality and safety information network structure is mainly the process of new node development. The factor influencing the new nodes is the process of selected connection of nodes. Overall Network Characteristic Factors Scale-free, power law and small world are usually used to describe the overall macrostructure of complex network.
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In fact, the phenomenon that the best get selected exists in many real network evolution processes, which means the new nodes in the network tend to connect the nodes with bigger degree. In the complex network of product quality and safety information, when the node develops selectively, it tends to connect with the nodes with bigger node degree in the network. Comparing with the ordinary nodes, famous nodes are more appealing. Through this kind of connection, it can be connected to most of news nodes. Besides, news reprinting chooses the content being reprinted according to the nature of the node. When the node selects whether to reprint the related content, it will connect with the other news it is interested in at random. The randomness is also shown in the complex network. Therefore, that the best get selected and the randomness of network are the main factors influencing the increase of node degree; the node with bigger degree value is usually more appealing and the probability of being connected is bigger; the node which is more appealing and with small degree value has greater probability of being connected; these nodes are usually the original websites of some important news; the node which has bigger degree value and is least appealing has smaller probability of being connected, for example, when some popular portals reprint other news, the other nodes tend to connect with the original node. Local Network Characteristic Factors The evolution development of product quality and safety information network is influenced by several factors such as individual differences and different transmission information of the node. The evolution mechanism of network includes original effect, evolution promoted by common properties and time importance effect. Original effect is that a website with some original news can easily become famous nodes in the whole transmission network. The nodes in the network mainly rely on the reprinting relationship to establish relation. The strength of original news capacity has direct effect on the position and the influence degree in the network transmission. According to the statistics, the portals such as Sina, Netease and PhoenixNet and some news websites such as people.com.cn have a large proportion of original news and the number of nodes to establish relation is obviously larger than other nodes. This is the direct reason of presenting the power law. In general case, the groups formed in the network have common properties and the properties foster the formation of network cluster. Obviously, for the same group, the network node it focuses on is usually the same. Also they pay attention to each other inside the group. When some event occurs, it will be transmitted inside the group quickly. There may be common properties between groups and these properties promote the connection between groups in the network. Then it can build the direct or indirect correlation between nodes and groups. The importance degree effect of event means the event being transmitted preferentially in the network. For example, two events occur one after another, event A and B. And the importance degree of B is highly greater than that of A. When A occurs, A is transmitted in the network following some law. When A is about to being transmitted on a large scale, B occurs, as B has higher degree of importance, people will pay more attention to it. Then A will enter the termination period or the attention of A will obviously decrease. Evolution Time Law Factor In the transmission process of product quality and safety event, the information amount changes over time. The whole transmission process of product quality and safety event can be divided into five stages of period of generation, period of outbreak, period of extension, period of remission and period of termination. The period of generation means that the product quality and safety information develops from nothing in this period; period of outbreak is that the period is about to start when the information appears on the Internet and the lasting time of this period will be several hours to a couple of days; the product quality and safety information of the period of extension is quickly transmitted. Under normal circumstances, the joining of central point of network can promote the development of the period; the period of remission is the period in which the product quality and safety information is under control. There are many reasons of this period, for example, people have lost the interest in the transmission of the event or the relevant departments of government control the transmission of the information. But itâ&#x20AC;&#x2122;s shown as the retard of information transmission; the period of termination is the subsiding period of product quality and safety event and the information of the product quality and safety event is basically no longer being transmitted.
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However, not all the transmission of product quality and safety event follows the above procedures. It also needs to combine with the properties of the product quality and safety event, the focus degree of media on the event and the transmission process of related events for consideration. Conclusion The paper uses complex network method to analyze the source channel distribution, transmission characteristics and influence factors of product quality and safety information in news websites. The paper makes the systematical analysis to the link characteristics, distribution of communities, overall network characteristics and local characteristics from static topology and dynamic evolution. The analysis shows that: news websites and traditional media are the main sources of product quality and safety information transmission; in the complex network of product quality and safety information transmission constituted by news websites, a few famous nodes play an important role in information transmission; the product quality and safety information transmission network conforms to power law distribution and it has the characteristics of small world, scale-free; that the best get selected and the randomness of network are the main factors influencing the increase of node degree; the network evolution includes original effect, evolution promoted by common properties and time importance effect. The deep analysis of network transmission of product quality and safety information is beneficial to building the product quality and safety information transmission model and prediction model. Itâ&#x20AC;&#x2122;s significant in building and improving the risk monitoring system of product quality and safety and evading the harm brought by product quality and safety problem effectively. ACKNOWLEDGMENT
Funding for this research is supported by the National Natural Science Foundation of China (Grant Nos.71271013), the National Key Technology R&D Program of the Ministry of Science and Technology (Grant No.2013BAK04B02). REFERENCES
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