Social Network Analysis

Social Network, a highlight in social networking, is a social structure made up of actors(which could be individuals and organizations) and ties between them(representing relationships between actors). 

Two Sociograms (graphical representation of social networks)

By studying the pattern of interaction between those actors in social networks, we can identify and locate influential entities and observe network dynamics. This is also known as Social Network Analysis which would be our topic today.

To better illustrate some metrics and basic concepts in Social Network Analysis, let's consider a simple Social Network as follows:

A sociogram consists of 4 students: A, B, C and D,
which represents their relationships between others

Fundamental Concepts:

1. Actor
Consider Student D alone. He is an actor and a social entity in this social network. In one mode networks, all actors are found having the same type inside. Other examples of actors are a crew in a ship, a region in a country and so on.

2. Relational tie
In the Network above, student A and D are linked by a line which we call a tie in Social Network Analysis. As this is an undirected graph, we can consider student A and D knowing each other. Ties can also be directional in other circumstances such as representing the subscriptions in Twitter, which is in one direction with the arrow pointing to the node of person being subscribed from the node of the subscriber.

3. Dyad
Dyad comprises a pair of actors and the tie between them. Student A and D is a Dyad in the previous graph.

4. Triad
It is a similar concept as Dyad but with 3 actors involved. It is composed of a subset of 3 actors and the ties between them in a social network. Student A, B and C forms a Triad as you may notice in the graph.

5. Cutpoint
Cutpoint is a node causing the network disconnected if it is deleted. Obviously, Student A is the cutpoint here because when it is deleted, Student D would be disconnected from others.

6. Bridge
It represents a tie that will make the network disconnected when it is deleted. In this sociogram, the tie among Student A and D is the bridge since Student D will be disconnected if the tie is broken.

Metrics:

1. Nodal Degree

It is the number of lines incident with it and can be regarded as a measure of the activity of an actor. A node with degree equal to 0 is called an isolate node.

Taking the previous social network as an example, we can find that the degrees of every node are as below.

Node	Degree
A	3
B	2
C	2
D	1

2. Density

Density can be treated as a measure of existing ties in a network out of the possible number. To calculate, we first assume L is the number of links and g is the number of nodes in a network. As the maximum possible ties between nodes are g(g-1)/2, the formula for calculating Density of a social network would be L/[g(g-1)/2], which gives 2L/g(g-1).

Therefore, the density of the above graph is: 2*4/4(4-1) = 2/3.

3. Sociomatrix

The relationship between each node in a social network can be represented by a sociomatrix, which has a size of g x g (g rows and g colums, g is the number of nodes). The entries in a sociomatrix record which pairs of nodes are adjacent and which are not. Each entry is called a cell in a matrix. ‘1’ will be input in the cell when there is a tie among two nodes in the network, while ‘0’ will be inserted when there are no ties between a pair of nodes, representing they have no relations.

Student	A	B	C	D
A	-	1	1	1
B	1	-	1	0
C	1	1	-	0
D	1	0	0	-

From the matrix, we can differentiate between directed and undirected graphs of social networks since for undirected graphs, the cell for 2 nodes in the row A for A and B(i.e. AB) must have equal value of the cell for the 2 nodes in the row B for B and A(i.e. BA). Matrix operations are important for Social Network Analysis, especially for directed graphs as patterns in the network can be highlighted by then.

4. Centrality

It determines the relative importance of a node in a social network, and tries to identify the most important nodes in the network. Here demonstrates 2 centrality measures:

a) Degree Centrality

As mentioned previously, degree of a node is the number of adjacent nodes the node has. Degree centrality is the sum of other nodes connected to that node in concern, which also represents activity and popularity of the node.

Provided that C_D(n_i) is defined as a degree centrality index in actor-level, and the normalized actor degree centrality is: 

where C_D(n_i) = d(n_i) and g is the number of nodes

From our example, a following result table can be obtained as follows:

Student	CD(ni)	C’D(ni)
A	3	1
B	2	2/3
C	2	2/3
D	1	1/3

b) Closeness Centrality

Closeness is based on the inverse of the geodesic distance of a node to other nodes in a network. It describes the average distances between one node and others node connected to it and identifies nodes that are relatively close to all other nodes. Closeness is taken on the inverse of geodesic distance to make sure that the larger the value is, the more important the node is in the network, which aligns with other metrics used in social network analysis.

Actor Closeness centrality is represented by:  

and normalized Closeness centrality is: C’_c(n_i) = (C_c(n_i))(g-1) 

where d is the shortest distance between 2 nodes and g is the number of nodes in the network

The following result table can be obtained from the previous social network:

Student	CC(ni)	C’C(ni)
A	1/3	1
B	1/4	3/4
C	1/4	3/4
D	1/5	3/5

We can see that Student A got the highest Degree centrality and Closeness centrality, which implies that he is the most popular among students and is relatively close to other students.

These metrics mentioned above facilitates the analysis of social network. Apart from collecting data in social networks and perform analysis to formulate marketing strategies by companies, organizations and even sports teams could even make use of it to examine the relationships between staff and members. With the rapid development of the mobile network and the increasing number of the users, it is undoubtedly that Social Network Analysis will have a more important role in the near future.

References:
[1] Wikipedia, Social Network Analysis
http://en.wikipedia.org/wiki/Cascade_(Social Network_Theory)

[2] Wikipedia, Social Network
http://en.wikipedia.org/wiki/Social_Network

[3] www.analytictech.com
http://www.analytictech.com/networks/whatis/htm

Cloud computing

During the previous two lessons, many topics were covered but a word being mentioned caught my attention - Cloud Computing. It is a hot topic in technology nowadays, where the name 'Cloud computing' was inspired by the cloud symbol which is often adopted in flowcharts and diagrams to represent the Internet. In general, it is about the delivery of computing resources over the Internet providing the ability for users to access the pool of the resources, which are normally owned and maintained by a third party.



                                                                                 From www.alchemysys.net

From the photo above, we can see that cloud computing allow different devices to access storages, hardware, network and services on their requests and is regardless of their locations. This acts as a factor of the rapidly expanding mobile market because using mobile phones and tablets can perform almost everything that we required to use PC to do so previously. For instant, by using the 'ePrint' service of HP, users are able to print their documents by their mobile phone remotely.



                                                                                     ePrint service of HP printers

Before going further to talk about the pros and cons of cloud computing, three common delivery models of cloud computing will be introduced:

1. Infrastructure as a Service (IaaS)

It is the most basic service model to provide virtual infrastructure and storage as well as hardware assets. This allows companies to only pay for the capacities they require and offers a leverage of possible additional storage space in data centres and servers. Amazon Web services is one of the largest IaaS providers.

2. Platform as a service (PaaS)

In this model, providers offer computing platforms with virtual machines, operating systems, application services and frameworks on their infrastructures. Users may make use of the cloud platform of the providers to develop applications and software solutions without the necessity of the managing and allocating the required hardware and software if they do it on their own.

3. Software as a service (SaaS)

SaaS is a operating environment with user interface, applications and management. Users enjoy services including emails, inventory control, database processing and suchlike through cloud clients offered by providers. Services are available everywhere since service providers would host the applications and manage the data so the need of installing the applications along with the corresponding maintenance and support on the computers of users is elinminated. Google Docs, a famous service which I believe you have used it, is a typical example of SaaS.

                                                IaaS is the basic model at the bottom. PaaS would extract some

                                                of its details, while SaaS would extract some of the details of

                                                both PaaS and IaaS.

 

Cloud computing, as a new concept, brings loads of benefits to us. One of them would be the accessibility of data and softwares. We may access our information store in the cloud at any place in the world provided that Internet access can be obtained. We no longer need to worry about forgetting to bring a USB which stores the information of the meeting tomorrow. At the same time, the danger of potential leakage of customer data due to loss of USB storages, which we can frequently hear from news, can be completed eliminated.

 

On the other hand, in business point of view, cloud computing could reduce operational costs enormously. Currently companies are required to pay for every software license installed in their computers usually with annual subscription fee. With cloud computing, applications would be in the cloud and requires employees to login. Softwares can be subscribed on a needed basis, which would lead to lower cost of using them. Moreover, as servers of cloud computing are not in-house anymore, the operational cost of companies can be further reduced.

 

Although using cloud computing technology is cost effective for enterprises, there are some shortcomings along that cannot be overlooked. Network availability would be one of them. As everything are stored in the cloud for cloud computing, once the network is down because of any reasons, we would not be able to access to the data and applications. It would be disastrous for banks and other companies which provide 7x24 services since the loss would be massive.

 

Another disadvantage would be the privacy and security concern. As in cloud computing, data and applications would be stored in third-party servers. They are out of our control and we can only rely on their protection measures against viruses and hackings. It would induce a sense of insecurity if you store important things such as credit card information, bank statements and so on. It is not rare as recently there is news about leakage of customer information including credit card data of Sony

 

Cloud computing would concededly be a trend of Computer technology for many years. With the rapid advancement of the technique, I believe cloud computing service will become more stable and reliable in the near future, where the disadvantages of it can be minimized. By that time, we can enjoy the benefits of it without worrying of the security and availablility of the service anymore!

 

References:
[1] Wikipedia, Cloud Computing
http://en.wikipedia.org/wiki/Infrastructure_as_a_service#Service_models

[2] Cloud Computing
http://searchcloudcomputing.techtarget.com/definition/cloud-computing

 

Social Influence and its impact

This time I would like to share about a topic I have learnt in the lesson - Social Influence. As you may know, it is a popular topic and research area in social psychology. While social psychology adopts scientific method trying to understand how psychological measures (thoughts, feelings and behaviors) of human beings are influenced by others, social influence is basically about the way of individuals being changed and affected by other people.

Social influence can always be found or discovered in many human activities, especially within communities and groups. One of the common reasons would be the tendency of people to adjust to behave and think like others, which is also known as Conformity. Below I take the Asch’s experiment conducted in the lesson as an interesting example.

A blue line is given on the left-hand side and the class was asked to decide which line on the right (A, B or C) is the same in length. About 1/3 of the classmates was told beforehand of the purpose of the experiment and was instructed to pick a wrong choice (line C) when the experiment was conducted in the class later. At the time it started and that portion of classmates provided their answer, it was found that the remaining classmates would also follow their choice although they may be in doubt or even thought that answer was incorrect. This is a kind of conformity under peer pressure which was demonstrated successfully by the class and proved that people would be influenced to change their minds and believes in order to humor the group.

Social influence can change our minds in a short period of time. A famous instance would be the shortage of table salt after the explosion of nuclear plants caused by the earthquake in Fukushima of Japan last year. Since by that time there was a rumour that eating salt could prevent people from the harm of nuclear radiation, in which they feared after the incident occurred, some people went to purchase bags of table salt in supermarkets and groceries. The rumour was spread out and resulted in more people believing and rushing to buy dozens of table salt even though in my opinion, some of them thought it had no such effect at first. During the peak time, the price of a small bag of table salt had once been raised to around $10. From this we can see the power of social influence. The effect of social influence is multiplied nowadays by the Internet as information can be shared in a relatively more rapid speed. We therefore must intelligently filter what we read in the Internet, have a second thought and judge if it is really the truth before believing.

Besides, you may also notice that social influence is able to alter our habits unintentionally. In the 90s of last century, with the development of personal computers and the Internet, the public started using computers as a communication tool. ICQ, an instant text message software, was invented for people to chat with friends who even lived overseas. In view of its convenience to contact, the number of people adopted its service increased quickly in short time. This was also an example of social influence. The more your friends use any software or application to communicate, the more willing you are to install and use it. It is because you would like to keep in touch with your friends and do not want to be considered as ‘OUT-OF-DATE’ when most people are using it except you. After ICQ, we have MSN, xanga and now Facebook and Twitter. People change the application using time to time and social influence is undoubtedly one of the reasons for that. Obviously, despite the negative impact of social influence mentioned in the last paragraph, social influence can also change our lives into a better way as nowadays, communication with family and friends are much cheaper and easier!

References:
[1] Wikipedia, Social Psychology
http://en.wikipedia.org/wiki/Social_Psychological

Social media and marketing

Hello everyone! This is my first blog here and I would like to share my opinion on social media and its impact to marketing business.

Newspaper, television or even radio channels were normally the media companies would make use of to advertise their products or services in the last century. People could choose and buy their commodities simply because they found the ads looked attractive to them. However, with the popularity of Internet usage, the effectiveness of the ads in traditional media is fading. Instead, marketing on social media quickly evolves and becomes a main stream of the industry. Social media used in marketing, as well as the marketing method will be further discussed below.

With the rapid development of mobile Internet access, it is now not rare to witness your neighbours browsing facebook, replying a tweet in Twitter or watching a video clip in Youtube during a bus journey, and I believe you must have been one of them sometimes. In fact, Facebook, Twitter and Youtube are among the most popular social media being used today. In view of this, companies would usually employ them as marketing channels (e.g. creating a facebook page, setting up a twitter account or recording a video and put it on Youtube) to promote their brands and products.

Starbucks Facebook page. They can promote their new beverages there.

Learnt from the lessons, there are several strategies to perform social media marketing like Reviews, Direct Social Recommendations, Derived Social Recommedations and so on. It is a little surprise to me that many websites which I often visit are actually using the strategies mentioned above. I will show some of them here and illustrate the methods they have used.

Hotels reviews and rating page in price.com.hk

 A restaurant reviews and rating page in openrice.com

These are the examples of websites using the strategy ‘Reviews’. By viewing the comments made by others, people can have a basic idea about the products/services before making a decision to buy them. It is extremely useful for booking hotels and restaurants and all other services, unlike purchasing an electronic product that people cannot have trials before really paying for their own experience. They would like to make sure the services they are going to receive worth the money they pay. Reviews acts as important references to them as they value opinions from peers. If the reviews enclosed photos with detailed comments, they will be of higher reference worth since the actuality is presented vividly in our eyes.

Share buttons in the top right corner for people to post this restaurant review on their facebooks

The website utilized the marketing strategy ‘Direct Social Recommendations’, which expresses emphasis on direct relationships to promote and recommend products and services. For instant, you may see that we can share our review of a restaurant directly in the website. By doing this, my friends are able to notice this restaurant in their Facebook newsfeed but not people who do not know me. 

Email to friends in order to earn points in groupon.hk

'Like' in Facebook to participate in a marketing event

Besides, this strategy are also formalized and packaged as marketing functions and campaigns of companies to promote their brands or products. Two common practices are: Email to friends and ‘Like’ in Facebook. Email to friends is to place a button or option for users to invite their friends to the current website or to become a member of it. In the first picture, you can see that it is encouraged by offering purchasing points once you successfully invite friends to become a registered user. The next picture is about a promotion campaign which requires participants to ‘Like’ in Facebook before answering the question. As our ‘Like’ activity would be shown in newsfeeds of our friends, this leads to a marketing effect with low cost.

Recommendation of hotels of Singapore in tripadvisor.com

Recommendation of jersey in ensport.com

Here shows two different examples of ‘Derived Social Recommendations’, which bases on statistic analysis to produce recommendations and offer to users. Benefited from the lessons, we are able to distinguish that the first one used user-based filtering to suggest hotels in Singapore while the second one offered another jersey based on item-based filtering methodology. To explain, user-based filtering will look for users who have similar interests, share the same rating patterns or come from the same regions and will make use of the feedbacks and ratings from those seemingly like-minded users to compute predictions and suggest to the current users. On the contrary, item-based filtering will create a database to analyze item-with-item relationships between different pairs of items by historical data and maybe even cookies, and extrapolate the possible items the user would be interested.

We have not yet covered all the marketing strategies that companies can make use of, but the above passages should have given you an insight about how social media is permeating into our lives. Companies which can properly employed social media marketing would undoubtedly be beneficial because they no longer require spending huge amount of money in advertising on newspaper and television. Creating facebook page and twitter, which would have much lower development and maintenance cost, could replace their function and may even have a more significant impact than the old approaches due to the popularity of the mobile internet access.

Of course, a coin always has two sides. Inappropriate social media marketing would cause negative influence to a company. In my opinion, the derived social recommendations are inconvenient because what they suggest is seldom the thing I look for. Same as direct social recommendations, they may hinder people from what they want, and cause annoyance for someone having limited time or in hurry. Besides, it is also known that there are companies hiring people to write reviews and give high ratings in websites, which makes the ‘Review’ strategy not as reliable as we first thought. These will all cause negative impact to the companies when users have bad experience of them since they can quickly share to their peers. Besides, to benefit from reviews of others, we can filter reviews by focusing on those who are made by people with more posts and go in deep of their reviews to differentiate if their wordings and descriptions are likely reflecting the truth. By doing this, I believe we can enjoy the advantages brought by social media marketing in many areas!