Information System

Information system

Definition: interrelated components working together to collect, process, store and disseminate information to support decision making, coordination, control, analysis, and visualization in an organization.

Information system can help in the company to collect information and data. Teacher’s register is a raw example of information system, the evaluation are Excel calculator sheets then Microsoft Access.

At the end, we have software applications (connected to databases and useful for data connection).

IS high level function

Usually, you start with an input — some data or goods that are introduced into the system. Then, this data and input are processed to produce an output. I can modify certain elements and receive feedback, allowing me to re-examine the input to understand its effect on the output.

Typically, customers are associated with the input, while suppliers are connected to the output. We use the information system (IS) to support decision-making and coordination.

There are also several actors involved: customers, who interact with our IS to purchase products; suppliers; and other stakeholders connected to the IS, such as regulatory agencies (e.g., government and tax authorities), stockholders (who invest money and expect returns), and competitors (who try to understand what we’re doing in order to outperform us).

Information system is not a computer system: IS involves the computer system. The computer system (hardware, software) and it’s a subset, a single component of IS (technical knowledge, organizational knowledge).

Case study: food delivery

• The input is when somebody wants to eat (idea of having a kebab).
• Then the process is the order on the app: customers, restaurant, rider.
• Then the output is the rider delivering the order.
• The regulatory agencies (Agenzia delle Entrate, Google Play, App Store, GDPR).
• Competitors (Uber Eats, Just Eat, Deliveroo).
• Stockholders (Delivery Hero).

Data vs information

An information system is a way to give meaning to data.

Data: streams of raw facts representing events occurring in organizations (e.g. business transactions) or the physical environment before they have been organized and arranged into a form that people can understand and use. If I get the raw data, it is unusable.

Information: data that have been shaped into a form that is meaningful and useful to human beings in processes such as decision making.

Rivalry: rivalrous good when consumed one party cannot be simultaneously consumed by others.

Excludability: when it is possible to prevent parties who have not paid for it from having access to it.

Return

Diminishing return: if I increase my market share there will be a point where I cannot get more and so I stabilize to it because I cannot grow my market share. Product or companies that get ahead in a market run into limitations (e.g. resources, market size) until an equilibrium of prices and market is reached. Typical of traditional production.

Increasing return: the more I get the more I can get more later in terms of market share. Information is very relevant even for this reason. Product or companies that get ahead in a market get their advantages magnified with time and can lock-in the market. Typical of high-tech industries.

Why? - Costs are mostly up-front (R&D) – Network effects – Familiarity and confidence – Lock in.

Information management operations

The information management operations are performed with two main objectives:

• Automation of activities: information systems focus on productivity and substitution of work with technology.
• Decision support (so I can visualize the information, with graphs and I can take decisions, like need more people etc.) I can do it without information system but using it is better. Help humans to evaluate quickly multiple alternatives.

Costs of information management

• Hardware and software.
• Personnel training.
• Management of IS (I have to change, modify, update my IS).

Organizations

People: managers, knowledge workers, data workers, production or service workers.

Structure: organization chart, geography, groups of specialists, products.

Business function: the single activities that have to be performed, specific task performed in a business organization.

Business process: the way the functions are done, how activities are organized. The process is the flow, the chain of the activity, the way they are essentially executed.

Structure Major business functions.

The IS is connected to all these functions. The IS should be able to cover all these functions, how to model the process used in these functions.

Enterprise is a specific case of organization who produces goods or services for profit.

Business process

The unique ways in which organizations coordinate and organize work activities, information, and knowledge to produce a product or service.

Common pitfalls

• Later version syndrome: is it necessary to have the latest (commercial) version of a software or hardware? iPhone 14 vs iPhone 15.
• Modern times syndrome: Is it necessary to automate an operation which may be easy to perform or irrelevant? Alexa.
• Internet/App FOMO: do we really need a website or an app for that?
• Lack of interest: the current way we manage our process does not require innovation.
• (Un)ease of use: the ease of use of the final system is not any business of the company.

Talking about information is not about talking about humans data such as words or documents, but there is a mid step that transforms data into information.

Views on information systems

There are many different viewpoints in the analysis and design of an Information Systems:

Evolutional: How to follow the evolution of technologies and of the organization. This view concerns the way the IS helps the evolution of the organization. An organization has within it a mix of different technologies that must be integrated with each other, i.e. the company must be able to manage them all together. The mix of technologies is not constant, but changes over time. It’s important to evaluate both the innovative and the conservative aspects within any IS, because for example the innovative aspect can in fact lead to decrease in costs.

Technological: tech components, architectures, performance, etc. This viewpoint tells us what technologies are used to build the IS, as well as the components that are part of it.

Functional: which applications for which business function. This viewpoint tells us what the IS does, what data it handles and what functions it performs.

Organizational: this view concerns the business level in which the IS is used. How it affects organization, processes, individual competencies, etc.

Economical: Effects of the IS on the structure of costs and/or the productivity of the company. Having some business functions managed by the IS lead to cost but even to benefits in terms of higher quality, fewer errors and more time-efficient implementations.

Transactional: How to manage economic transactions (internal and to outside). How the information system handles data and the way they are modified.

Design: Related to software engineering and project management. Based on design choices of the information system (software point of view).

Decisional: Support tool for decisional processes. Support decision making processes within the organisation.

Management: Who is in charge and how it is located in the organization, how investments are planned and realized.

Analysis model

• Functional: What activities the system must perform.
• Organisational: Who should do what activity.
• Technological: How these activities can be carried out (implementation).

The IT model (Information Technology)

The IT model describes how the IS is built:

It is divided into two main sub-models:

• Technological Model: description of the hardware architecture. IS as a set hardware systems and their network connections.
• Application Model: description of the software architecture.

Processing architecture

• Mainframe era (60s to 70s): Centralized computing and data processing.
• Client-server era (80s to 90s): One computer (the client) can request for a process or data from another computer (the server) attached to the network.
• Web-based client server (00s to 10s): the application software resides entirely on a network server and the client computer only needs a standard browser.
• Cloud computing era (10s and beyond): Use of ubiquitous, cheap, on-demand access to a pool of configurable computing resources (third party infrastructure).

Client-server (C/S)

Architecture where client processes request services offered by server processes.

• Client system: typically running on wide range of devices (e.g. work station, smartphone, tablet) where a portion of the presentation layer reside.
• Server system: hosting the rule processing (application server) and data management (data server).

A processing architecture must satisfy a few basic requirements:

• Response time: the time needed for the delivery. The interval between the request and the display of the response; depending on the application the system shall be more or less reactive (e.g. ATM vs. electricity meter).
• Scalability: the bigger is the organization, the more this is a relevant parameter. 5 x 9s is the response time for a software in the 99,999% of cases. It’s the work load a system is able to sustain, typically expressed in number of concurrent users. How my system is able to manage a larger number of users at the same time.
• Availability: the system is available without breakage. It’s the percentage of time the system is working (typical IS should be around 99,95%).
• Reliability: ability to operate the IS even in the event of faults: fix the fault without interrupting the service and without customers noticing.
• Another parameter that should not be here but it is actually here is cost.

IT selection

The process of selection of hardware is called IT Selection.

• The selection of the IT model takes into consideration costs, performance, sizing etc.
• Looking at the technology evolution allows considering long-term costs.
• Other analysis dimensions include the growth perspectives of the organization.

Network architecture

The distinct systems of a processing architecture communicate by means of networks that transmit digital information. According to the size (extension) they can be:

• LAN (Local Area Network): range few km, bandwidth 1-10 Gbps.
• MAN (Metropolitan Area Network): urban area range, bandwidth 10 – 100 Gbps.
• WAN (Wide Area Network): regional or national range, bandwidth 1 Tbps and beyond.

Network working modes: intranet, extranet and internet

Intranet “something just between us” private data.

The internet is a public network that aims to allow all nodes (users) to communicate with each other. Intranets were born to meet the data protection needs of companies, are private networks, normally internal to a company. Intranets are disconnected from the other networks. This prevents access to data from outside the company, and thus solves the problem of data security.

Finally, Extranets are private links created by means of a public connection between several intranets. Extranets allow access from outside to certain information, but this access is only allowed to intranets that have the authorisation to do so.

Virtual Private Network (VPN): It is supposed to connect two different part of the same organization physically located far away.

The application model

IS as set of software applications. Typically with three layers:

• Presentation: it defines the interaction with end user via GUI (Graphical User Interface) or different inputs (e.g. Keyboard).
• Business rules: Rules constitute the logic driving the processing of data entered in the IS through the Presentation layer.

They interact with the presentation and the data layer. They may include computations, logical operations, data analysis. Algorithms and rules to process, control and extract data.

• Data: The database is a permanent storage of data organized according to a schema (e.g. Oracle, MySQL, Access). The selection of data to be stored is linked to the organizational needs and may imply various costs.

The organizational model

It considers the IS as a service offered to a business unit or a group inside the enterprise.

The organizational model can be described with:

• Organizational charts (at macro and micro level) hierarchy level.
• Linear Responsibility Chart (LRC) permissions.
• Pools/Lanes (BPMN Diagrams).

The functional model

Describes what the IS should do, abstracting from how it can be done (the IT model the requirements of the model, independently from the final structure).

• Processes:
• Activities, functions.
• BPMN, UML activity diagrams.
• Data: UML class diagrams, Entity Relationship (ER) diagrams.
• Interactions:
• Use cases, UI mockups.

Processes

Set of activities described by roles, input and output, with the objective of producing products or providing services BPMN.

Conceptual model: data

It describes the type of data managed by the system UML.

And IS can work on master and transaction data:

• Master data: static lists (customers, suppliers, products) that change rarely.
• Transactional data: dynamic events (orders, shipments, etc.).

Interaction

Modeling of how the users can perform operations by using the IS use-case.

They can be described through use cases and mock-ups models.

Conceptual modeling

Organizational model is about how business is organized. The focus on this course is all to functional model.

The UML language (Unified Modeling Language), we will focus on class diagrams (conceptual modeling) and use case diagrams (interaction modeling).

But has several diagrams:

• Class diagrams conceptual modeling.
• Activity diagrams.
• Use case diagrams interaction modeling.
• Sequence diagrams.
• State charts.

Conceptual modeling is the formalization phase of the requirements through a model described from the stakeholder’s perspective.

Requirements analysis taking information.

Conceptual modeling putting information in boxes.

Goal

• Capture the main (abstract) concepts of the IS find the main CONCEPTS.
• Associate characteristics (data) to the concepts big concepts but tiny information related.
• Define the relationships between concepts relationships between main concepts and tiny details.

Class

A class represents a set of objects with:

• Common properties.
• Autonomous existence.

Using a singular common noun (city, department, employee).

Don’t put “+” but for visibility put “-”, so it’s private and not visible.

The object models a specific item (material or immaterial) within the system.

It is characterized by:

• Its identity.
• Its attributes (or data, or properties).

Attributes

An elementary property of a class, characterized by name and type. It associates to each object a value of the corresponding type. In the example of Classname is “+ field: type”.

Association

Association represents logical link between two classes. An occurrence of an association is a pair of occurrences of objects, one per class. The first thing to do is to start from the classes.

The association can be with arrows or not, but arrows are not used.

Example. Each student can follow more courses and two students follow the same course.

Usually you need a direction like students with course (attend).

But also Recursive Associations: association occurring between a class and itself (it’s used in a hierarchy father-child).

Recursive associations is an association occurring between a class and itself. For example person can have a recursive association named “is_friend_of”.

Link

While the association is at class level, the link is at object level: it represents an instance of an association between objects.

Multiplicity

Maximum and minimum number of links in which an object can participate. Should be specified for each class having an association.

A wheel can be mounted on none or at most one car.

Only three values are used: 0, 1, * (many).

• Minimum: 0 or 1 if the minimum is 1, there’s a mandatory participation.
• 0 = optional participation (for each object).
• 1 = mandatory participation (for each object).
• Maximum: 1 or *.
• 1 = each object is involved in at most one link.
• * = each object is involved in many links.

Intermediate classes

An association is a subset of the cartesian product. It can represent the presence (or absence) of a link between two objects. NOT the presence of multiple links between the same two objects.

An intermediate class can solve this issue. The intermediate class is linked with class A and B, allowing an object of class A to be linked with multiple objects of class B.

Derived attributes that can help you to optimize the model.

Association class

The association class define the attributes related to the association.

A link between two object includes:

• The two linked objects.
• The attributes defined by the association class.

Limitation:

Example: A Consultant can work several times for the same Company. This configuration cannot be represented by an association class. It can only be represented through intermediate class.

Specialization / Generalization

B specializes A (or A is a generalization of B) means that:

• B has the same characteristics of A. B can’t remove information from A.
• Attributes.
• Participation in associations.
• B may have additional characteristics (it does not need to).

In the example a person could be an employee or a student, employee and student are subsets of person.

Specialization types

Totality

• Total: the union of the derived classes covers all the base class plants could be exotic or not.
• Partial: some object does not belong to any of the derived classes people could be employee, students or neither of them.

Exclusion

• Mutual exclusive: an object can belong to at most one