Design and Simulation Analysis of Multi-Agent Online Dissemination Model on the Basis of " The Spiral of Silence " Theory

This article studies the classical theory of communications—the Spiral of Silence. The key factors are extracted for multi-agent modeling and simulation with Netlogo. It turns out that opinion climate is the external formation of the Spiral of Silence. Besides, the size of opinion climate has no direct effects on the Spiral of Silence.


Introduction
The innovation of "The Spiral of Silence" theory has attracted many researchers under today's network communication environment, some scholars believe that the the Spiral of Silence in cyberspace is weakening which plays a new role in network media. GAO Xianchun et al. think that: "Mass media and specific individual communities make a difference in the new media environment constructed by Internet, mobile phones and others which are in the construction of specific event. And they both trigger the double helix of silence. In other words, mass media and individual communities form spirals respectively, meanwhile, both games lead to opinion cassette which is the factor affecting individual perception. As a result, the double helix of silence influences individual expressions of opinion. " (GAO Xianchun et al,2014) Yang Zhibiao supports the thory despite of its assumptions and limitations. In his opinion, it is still available in network environment. What is more, "the spiral of silence" is alive with "Against the Spiral of Silence".
However, other scholars believe that the Spiral of Silence is still spinning in the new era. To explore the views of "Gay Bullying", Sherice Gearhart et al. investigate 760 participants. It was found that the the Spiral of Silence still exists in social networks, besides, personal ideology will also have an impact on the willingness of expression (Sherice Gearhart et al, pp. 18-36, 2014. ). Li Chuansheng points out that the Spiral of Silence still works because of the fear of isolation and group pressure in the network. What is more, the Internet has a character of anonymity, but net users' behavior is not unrestricted and complete freedom does not exist which due to group norm and social norm in the network community. That is the reason why the Spiral of Silence is still in the spin (Li Chuansheng, pp. 4-12, 2014). Na Yeon Lee et al. carry out a series of studies on controversial topics among journalists who work for nine national newspapers and two networks broadcasting corporation through the empirical research. It turns out that the Spiral of Silence still exists, especially in the social networking site-Twitter (YL Na, pp. 443-458, 2015). Cheng Yao also points out that because of unconverted habits of netizens, squelch on the Internet and attention which the country begins paying to supervising public opinion online, the Spiral of Silence will coexist with public opinion on the network for a long time in a more subtle way. Moreover, according to a report released by the Pew Research Center and the Rutgers University, social media such as Twitter and Facebook will contain the diversification of views, hinder public affairs debates and limit people to state their views. Especially when they find that their opinions are different the fear of isolation; climate of opinion, and quasi-statistical sensewith friends'. The report also said that very few people who use social media regularly express different points of view offline.
In order to study the impacts mechanisms of the Spiral of Silence, Scholars adopt empirical research through questionnaire to explore the impact of " the climate of opinion " -one factor of the Spiral of Silence. In Chang Ning's research, it is found that post-90 college students adhere to the "expression"of the highest degree in real life. Unexpectedly, under the anonymous network, post-90 college students tend be more silence. The study also shows that the anonymity of the network is not the main factor to promote the expression. The agent changes, in includes th in the prog "radius". P certain "p "count-aro

Simula
(1) Propert  Vol. 9, No. 4;2016 Most Internet users will try to avoid isolation caused by separate attitudes and views. When agents find their own views are different from those of most Internet users or those of the mainstream media, they will not tend to express their opinions. Instead, they may choose to change views to correspond to the mainstream views online.
(2) Settings of initial state The slider--initial-chance is set to represent the distribution of initial state. The proportion of positive and negative opinions will vary when setting different ratios. Besides, The "initial-people" stands for the number of people who know the event and express their views. The "radius" is on behalf of the size of the climate of opinion in which the agent can be affected. According to the spiral of silence, the fear of isolation is inherent nature of the people, thus the initial values of "r-afraid-index" and "g-afraid-index" are set to 50 each.
( ]of turtles in-radius radius)] end b. Changing Attitudes: when the value of the fear of isolation reaches a certain critical value, Internet users may change their views. What is more, when corresponding to the majority, agents will be willing to express their opinions and try to influence other agents. That's why there is a process called "hatch", here's the code.
to change-color if red-turtles > green-turtles [ if color = green and random r-afraid-index < 35 [set color red fd random 10 hatch 1 [set color red fd random 10 set r-afraid-index 50 ]] end c. The ultimate source--"fear of isolation": the fear index will change accordingly when the individual is affected by the surroundings. In addition, different agents have different degrees of changes on the fear index. This part of the code is as follows: to change-afraid-index if red-turtles > green-turtles [set r-afraid-index(r-afraid-index -random 10) set g-afraid-index(g-afraid-index + random 10)] if red-turtles < green-turtles [set g-afraid-index(g-afraid-index -random 10) set r-afraid-index(r-afraid-index + random 10)] end

Analysis of Experimental Results
The initial value of " initial-people" is set to 880 which represents the number of people knowing the event at the first time. The initial value of " radius" is set to 1. The percentage of two sides is randomly decided and different percentages have direct impacts on future climate trends. In this paper, the values of initial-chance are 0.1, 0.3, 0.5, 0.7 and 0.9 respectively. Parameters are shown in Table II.. No. initial-people initial-chance radius r-afraid-index g-afraid-index Then, Pres to change, follows. org Experim ss the "go" but , and the corre As can be ratios in th opinion re silence do that is to s picture abo minority o In order to the climate the study,