05.03.12

Database class today will talks about monitoring and tuning. After talking about normalization on previous week, now we have to admit that not all normalization will help us in making a good database. A normalized database could lead to inefficiency, so we can try fix that with denormalization.

We can do the denormalization with steps as stated below:

1. Combining 1:1 relationships
2. Duplicating non-key attributes in 1:* relationships to reduce joins
3. Duplicating foreign key attributes in 1:* relationships to reduce joins
4. Duplicating attributes in *:* relationships to reduce joins
5. Introducing repeating groups
6. Creating extract tables
7. Partitioning relations

But, although we can increase the efficiency, the denormalized form can slow down the updates.

We do monitoring and tuning to monitor operational system and improve performance of system to correct inappropriate design decisions or reflect changing requirements. We have factors that help us to measure the efficiency, such as:

• Transaction throughput:  number of transactions processed in given time interval.
• Response time:  elapsed time for completion of a single transaction.
• Disk storage:  amount of disk space required to store database files

This is the end of database class.

06.03.12

This week Computer Network class will talks about making connection. The lecturer taught us that the connection to a peripheral is often called the interface. The process of providing all the proper interconnections between a computer and a peripheral is called interfacing.

There’re 2 types of Characteristics of Interface Standards:

1. Official standards
2. De facto standards

We also have 2 Important Interface Standards:

1. EIA-232F – older standard, originally designed to connect a modem to a computer
2. USB (Universal Serial Bus) – a newer standard, much more powerful than EIA-232F

There’s also firewire, a low-cost digital interface, capable of supporting transfer speeds of up to 400 Mbps, and hot pluggable.

Next is about connection, we have 2 types of connection: Asynchronous connection and Synchronous connection. But we have additional type (the third type) called Isochronous Connections, which defined at the data link layer used to support real-time applications. Typically an isochronous connection must allocate resources on both ends to maintain real-time.

The lecturer then told us the term of half-duplex systems, which can transmit data in both directions, but in only one direction at a time, and full-duplex systems, which can transmit data in both directions at the same time.

>to be continued<

Now I’ve already in my third week for my 1^st semester, and I started to get used to the course in this master degree.

Below is the summary of my course this week, please help me to review them. Thanks

27.02.12

Today’s class is research methodology class. We talk about policy research.

Policy research is something that related to compose the policy, like competency standard. In policy research, we have policy making and policy analysis activities.

Policy making is about how we can produce a better and more suitable policy for an organization (problem solving). Policy analysis is something that assesses current existing policies, checks whether the policies are already effective enough (evaluative). It also sees the impacts for the organization and for the citizen. Then it will do a gap analysis to find the root causes, and provide some recommendations.

Policy itself could be found in various things like strategy, organization’s structure, SOP (standard operational procedure), governance, etc.

But we have to assured that an evaluative research is not always asses the policy.

The lecturer then taught us about problem that we faced in construct a policy research, the problem is about experience. The person who will make this policy should mastered the concept, and in a position that allow them making the policy.

Next, we have general framework for policy research:

1. Background – why do we conduct this research? Gather the problem and facts, find root causes by fishbone analysis, create research question, define the scope and advantages.
2. Literature study – finds relevant theories to solve the problem, also other relevant previous research, then develop theoretical framework. Literature study is a result of thought processing, process of the theories. This is not a collection of various theory.
3. Develop research methodology – what are steps required and how’s the output? Data collection methodology. Is it inductive or deductive, a positivism or interpretivism, a quantitative or qualitative research and so on.
4. Data collection – do we gather a primary data or a secondary data? Should we perform a focus group discussion? And so on.
5. Data analysis, develop conclusion, and Recommendation.

Policy analysis consists of define the problem – build hypothesis – test (statistical test) – expert judgment – output (gap analysis).

That’s all for today’s class.

28.02.12

I have computer network class today, and I learned about conducted media, and wireless media. Conducted media consists of twisted pair wire, coaxial cable, and fiber optic.

Twisted pair wire is a two or more pairs of single conductor wires that’ve been twisted around each other. Coaxial cable is a single wire wrapped in a foam insulation surrounded by a braided metal shield, then covered in a plastic jacket. We have baseband and broadband coaxial technology. Fiber optic cable is a thin glass cable approximately a little thicker than a human hair surrounded by a plastic coating and packaged into an insulated cable.

For wireless media, we have terrestrial microwave, satellite microwave, and cellular telephone.

Terrestrial microwave is land-based and has line-of sight transmission. Satellite microwave has the signal travels from a ground station on earth to a satellite and back to another ground station. Satellites can be classified by how far out into orbit each one is (LEO, MEO, GEO, and HEO). As for satellite configuration, we can do it in two ways, bulk carrier configuration and multiplexed configuration. While for cellular telephone, it creates cells that have its own transmission tower and set of assignable channels.

Other example is pager. Pager is a one-way communication service that uses ground-based and sometimes satellite-based systems. There’s also infrared transmission, which use a focused ray of light in infrared frequency range. As for WAP (wireless application protocol), it allows wireless device like PDA, pagers, and so on to access the internet. We also talk about Bluetooth, which is a radio frequency specification for short-range, point-to-multipoint voice and data transfer. Then there also a wireless LAN, a technology that transmits data between workstations and local area networks using high speed radio frequencies. Free space optics, on the other side, is a technology that uses lasers, or more economical infrared transmitting devices. Then we have ultra-wideband, which broadcasts over wide range of frequencies simultaneously, it uses such low power that it can’t interfere with these other sources.

When choosing a media, we have some aspects to consider like cost, speed, distance and expandability, environment, and security.

That’s all for today’s class.

29.02.12

I have PM-RPL class today, and I continue to learn about CMMI.

I learned that each level has it owns KPA (key process area) that should be accomplished in order to reach the goals. Each process area has practices that has to be done by the organizations.

The characteristic is that the higher the level will have more process area that should be done.

There is no process area for level 1, because level 1 is an ad-hoc process. As for level 2, we’ll re-run the methodology that succeeds the previous level. In level 3, all project use the same methodology (defined).

There are various kinds of process areas, one of the example is requirement management.

We also do software project planning, the purpose is to make the planning to manage software project and to perform software engineering. Then we can make a work breakdown structure, which breakdown the bigger work. The bases for creating WBS are the used methodology, and breakdown product (based on subsystem).

Then we talk that CMMI is integration and improvement, and that CMII consist of 2 types: staged and continues. Staged CMMI’s maturity level has some stage such as initial – managed – defined – quantitatively managed. Each process area has specific goals and generic goals.

In an organization, we run generic practice when we do the practice we also run the specific goals, if all of that finished, then we can enter to the next stage.

And we reach the end of PM-RPL class.

01.03.12

This time PSI class talks about business process. Business process is an activity order based on inputs to produce an output for clients.

We have 3 types of business process, they are:

Still like the first post, it will explain everything I’ve learned on my second week

20.02.2012

The courses I took on the second week started from RESEARCH METHODOLOGY AND SCIENTIFIC WRITING CLASS. In this class, we talk about the “TRUTH”, start from the definitions, and about types of truth. There are 3 types of truth: faith-based truth (believed, for each individuals, absolute), perception-based truth (different from one to one), and scientific-based truth (needs scientific inquiry). After that, we continue to discuss the history of scientific inquiry: dark age – enlightment age – modern age – post modern age. We also talk about scientific inquiry, which is a variety of methods to explore the natural world and proposed explanations based on the evidence they find.

The lecturer then asks the class about what’s the difference between science and art. He said that an art is a result of imagination, while science is a result of verification. But, an imagination that verified scientifically will become a science, too.

There are 2 mainstream in research: positivist research and interpretive research. Positivist research is a paradigm that believes something is the truth if and only if there are facts which can be observed and proven. Interpretive research is a social phenomenon, which considers the truth as something that is relative, it depends on human’s ability and assumptions. There is also another stream, called appreciative inquiry. This is an approach with strength exploration paradigm in order to decide which way the company should be heading?

We also talk about 3 kinds of Logical Thinking: Inductive Reasoning, Deductive Reasoning, and Abductive Reasoning. Abductive reasoning is a quick decision of specific matter, in order to make more focus

Then, we talk about varieties of logical fallacies: generalization, irrelevant conclusion, affirming the consequence, arguing in a circle, non sequitur, loaded question, misinterpret opponent’s position, equivocation, division fallacy, and misplaced concretion. Then we move on problem’s discussion, include how to make problem analysis.

That’s all for RMSW class

And tonight, I have database class.

DB class this night talks about entity-relationship-attribute.

The lecturer taught us that the decision to make an object become an entity or an attribute is depends on user’s need. If the user needs to see the details then we should make it an entity rather than an attribute.

A relationship in database has various types. The first one is unary relationship, which only involves single entity. The second one is binary relationship, which involves two entities. The third one is ternary relationship, which involve 3 entities. And the last one is N-nary relationship, which involves n entities. There is also a term called multiple relationship, that has more than one relationship on two same entities. For example:

A relationship might has an attribute, but it’s fine if it doesn’t. Attribute also has many types, such as simple attribute, composite attribute, single-valued attribute, multi-value attribute, and derived attribute.

We also talk about key. A key is a characteristic that differs one entity from another, in a form of an attribute.

We have candidate key, primary key, and composite key. Candidate key is a list of keys that are not picked as primary key. Composite key is a candidate key that has more than 1 attribute.

Bellow is an example of an entity that has multi-valued attribute:

Database also has 2 entity types: strong entity and weak entity. Weak entity existence is dependent on strong entity. The ERD’s important constraint in relationship is cardinality and participation.

Next discussion is the enhanced ER modeling. We discuss the specialization and generalization in ERD. We have subclass and superclass relationship, which may have overlapping or disjoint criteria. If a generalization has optional characteristic, it means that not all superclass’ member must become the subclass’ member, too. Mandatory relationship means that all member of superclass must become member of subclass, too. The inheritance of superclass’ attribute to the subclass’ attribute is called attribute inheritance.

We also have mapping steps, to help us do the mapping right.

First of all, we can map the strong entity then move on mapping the weak entity. Then we can start mapping the 1 to 1 relationship, followed by 1 to many relationships, then we can handle many to many relationship.

That’s all for today’s class.

–

21.02.2012

This time the class discusses the Computer Network’s class talks about Fundamentals of Data and Signals chapter.

The introduction is the definitions of terms that will be used in this chapter, include definition of convergence, data, signals, transmission, followed by some examples of those terms.

Types of signal: continuous, discontinuous, discrete, and non-discrete.

The lecturer also explains the definition of amplitude and frequency, which are components of a signal. Frequency has related properties such as period, bandwidth, spectrum and attenuation. A period is a time within one cycle. Spectrum is a range of frequency. A bandwidth is a difference between the highest frequency and the lowest. There’s also attenuation, a reduction of signal’s strength. A signal also has a phase, which is a relative position over the zero point.

We can compute signal strength by following this rule:

There are some techniques to convert digital data into digital signal, such as NRZ-L, NRZ-I, Manchester, Differential Manchester and 4B/5B Encoding.

There are also techniques to convert digital data into analog signals, like amplitude modulation, frequency modulation, and phase modulation.

For data transfer rate, can be computed by this equation: , where f is signal frequency, W is signal power, and N is noise power.

As for converting analog data into digital signal, it can be done by pulse modulation and delta modulation. We also have 3 data code sets: EBCDIC, ASCII, and Baudot Code.

That’s all for today’s class.

22.02.12

Today’s class of PM-RPL talks about CMMI. CMMI is a model, framework, and concept to measure the capability of an organization.

The lecturer also taught us that a mature organization will have some sort of rules/plans/tactics that are implemented inside the organization. Such a mature organization won’t fall just because one of their best employee leave the company. Matured company will naturally held a review whenever they face failure, they learned from their mistake, then do an adjustment to make an improvement. This review activities not only be done when they face failure but also when their project success.

So, CMM will help us to differ the high quality software development company with the low quality company.

SW-CMM has 5 levels of software maturity:  Initial, Repeatable, Defined, Managed, and Optimizing. We can use CMM by hiring a certified assessor to conduct formal evaluation. We also could conduct an internal assessment by sending the company’s worker to an official CMM training.

Next is about CMMI, a model that consists of best practices that address productivity, performance, costs, and stakeholder satisfaction. CMMI can help the company to set process improvement goals and priorities, and provide a yardstick for appraising current practices. The lecturer also talks about the values of CMMI.

Then we move to KPA (key process area), for each organization’s maturity level, SEI has set the KPAs as a reference to step on the next level. We have some common features / factors in implementation and institutionalization, the factors are activities performed, commitment to perform, ability to perform, measurement and analysis, and verifying implementation.

By implementing CMMI, we could have quantifiable benefits such as reduce the cost of development, better level of control on project changes, reduced time to market, better resource allocation, increase percentage of project on-time and on-budget, and so on.

That’s all for today’s PM-RPL class.

23.02.2012

Today, I have PSI class, which mainly talks about best practices, today.

We discuss about the challenges of software development, which is a job for teams. The challenges are about larger teams, specialization, distribution, and rapid technology change. The fact that we faced nowadays is that 68% IT projects completed, but from those completed projects, we only have 17% that run on-budget, so the remaining are 32% cancelled, and 51% projects run over-budget. So we have many successful software development projects, but we also have many failures.

Some symptoms of software development problems: inaccurate understanding of end-user needs, inability to deal with changing requirements, poor software quality, team member in each other’s way unable to reconstruct, and so on. To solve these problems, we have to find the root causes, which can be done by using best practices of software engineering. The best practices consists of develop iteratively, manage requirement use component architectures, model visually, verify quality, and control changes. We should conduct the best practice iteratively so we can accommodate changing requirements, mitigate risks earlier, get early feedback from end-users, result in a very robust architecture, and so on. We also need requirements management to make sure we solve the right problem and build the right system. Then we make visual modeling of the software to improve our ability to manage software complexity.

Then we move to UML (unified modeling language), which is a language for specifying, visualizing, constructing and documenting the artifacts of a software-intensive system. Besides that, we need to control changes to software, to prevent chaos when running parallel development.

By implementing the best practices, we can achieve result: a software that is on time, on budget, and meet the user’s needs.

That’s all from today’s PSI class.

24.02.12

Today is Friday, and usually I won’t have class today, but this is a special case, since my TSBD lecturer couldn’t come on next Monday, so the replacement class will be held today.

Today’s call of TSBD mainly talks about the term Normalization.

We need to normalize our database in order to prevent the repetition of information (redundancy), and to avoid the inability to represent certain information, we also want to minimize the presents of null values. Data redundancy can lead the update anomalies to happen. Update anomalies has some types include insertion, deletion, and update. We have goals of normalization, such as to decide whether a relation is in a “good” form, we can decompose the relation to make them good. The decomposition is based on functional dependencies theory and multivalued dependencies theory. Functional dependency is a relation between attributes, when each value of the attribute is associated with exactly one value of the other attribute. In FD, we have a determinant, which is an attribute on the left-hand side of the arrow.

We also have terms like full functional dependencies. Full functional dependency indicates that if A and B are attributes of a relation, B is fully functionally dependent on A, if B is functionally dependent on A, but not on any proper subset of A. Then we have transitive dependencies, which describe a condition where A, B, and C are attributes of a relation such that if A → B and B → C, then C is transitively dependent on A via B.

Decomposition itself has 2 properties, they are: lossless-join property, and dependency preservation property.

We have 6 steps of normalization process, start from 1NF, 2NF, 3NF, BCNF, 4NF and 5NF. Normally, it’s enough for us to just reach the 3NF.

The characteristic of 1NF is a relation with no multivalued attributes, we’ll have to decompose the relation of it has multivalue attributes. 2NF is achieved when the relation is in 1NF and every non-prime attribute is fully functionally dependent on the candidate key. Next is 3NF, which can be achieved when a relation achieved 1NF and 2NF and in which no non-prime attribute is transitively dependent on the candidate key. Then we have BCNF, which can be achieved if the determinant is the candidate key.

That’s all from today’s class, and also end of this week’s course

See you again next week

I’m Stella from MTI, Fasilkom UI, Jakarta, Indonesia

This blog will become my documentation and also a kind of report of my current study, as master’s degree student. I’m currently in the middle of practicing my english, so please understand if my grammar looks bad.

I’ll try to share what I’ve got from campus by re-write my notes at class, per day and also per course.

13-02-2012

I started my master’s degree program in February 13^th, 2012. My first subject was Metodologi Penelitian dan Penulisan Ilmiah (Research Methodology). In this class, I learned about how the human’s way of thinking was divided into 3 types: Rational, Emotional, and Cultural.

Rational is related to creativity, knowledge, experience, and a logic reason, while emotional is always concern about feelings and emotion. On the other hand, cultural type is something whose background can’t be argued, because it’s involved believes and faith.

So, we can’t really explain something that use emotional and cultural type of thinking. But those 3 types’ collaboration will become a good way of somebody’s thought.

Rational has 3 characteristics: it must have a good data, a good theory, and a good methodology.

So, if we talk about research, then we will talk about rational type, that covers those 3 characteristic of rational type.

As we talk about research, there are 2 kinds of research:  basic research and applied research.

Basic research’s purpose is to develop new theory (e.g. new algorithm), this is not always relevant with our daily life. It has a universal’s conclusion.

Applied research, on the contrary, has localized conclusion that more relevant with our current daily life with a scientific approach that is combined with mental model (we can tolerate subjective thing).

For research itself, it has the objectives to solve problem(s) and to test the hypothesis. Research is a careful and systematic process to answer a problem of interest. It covers data, theory and methodology.

Research has some characteristics, such as:

1. Research Question
2. Clear articulation of goals
3. Follow specific plan / procedure
4. Often divide main problem into subproblems.
5. Guided by specific problem, question, or hypothesis.
6. Accept certain assumption.

Next is about method. Method is a subset of methodology. Methodology is systematic steps, and a collection of method. As for method, it’s more technical, for example data collection method.

And that’s all for Research Methodology class that day.

That night, I was attending a database class. I was learning about definitions of data, database, information, metadata, database management system, and database system. After that, the class continues with the explanation of the stages of database system development lifecycle. This cycle consists of database planning, system definition, requirements collection and analysis, database design (include conceptual, logical and physical database design), database management system selection, application design, prototyping, implementation, data conversion and loading, testing, and maintenance. Each of the stage was described by the lecturer and I’ll try to share that in my blog, here.

Database planning is the stage when we manage all activities, which allow stages in the lifecycle to be realized as efficiently and also effectively as possible. System definition is when we start to make description about the scope and boundaries of the database system and also the major user views. Requirements collection and analysis is the stage when we collect and analyze the information about the part of organization that need to be supported by the database system, and when we use the information to identify the user’s requirements of new system. This stage contains the centralized approach and view integration approach. Database design is a process of creating a design for a database that will support the enterprise’s mission statement and mission objectives for the required database system. Database Management System (DBMS) selection is a stage when we select an appropriate DBMS to support the database system. Application design is a stage when we design the user interface and application programs that use and process the database. Prototyping is a process when we build a working model of a database system. Implementation is a physical realization of the database and application designs. Data conversion and loading is a process of transferring any existing data into new database and converting any existing applications to run on new database. Testing is a process of running the database system with intent of finding errors. Maintenance is a process of monitoring and maintaining database system following installation.

That’s all I learned that night.

(source: Slide from Database System Technology’s class)

14.02.2012

Today’s class is Data Communications and Computer Networks.

The class show me that nowadays, most of our activities are using the computer network. The lecturer also talks about the definitions of terms that used in this course.

There are several categories of computer network:

• WAN (wide area network)
• MAN (metropolitan area network)
• LAN (local area network)
• PAN (personal area network)

After that, the lecturer give definitions of some terms such as data communications, voice network, data network, telecommunications, and network management.

Then, the explanation moves on to talks about the computer networks basic configurations. There are several types configuration such as: computer terminal to mainframe computer, microcomputer to mainframe computer, microcomputer to LAN, microcomputer to internet, LAN to LAN, LAN to MAN, PAN to workstation, LAN to WAN, sensor to LAN, satellite and microwave, and wireless and wired telephone to network.

The lecturer then asks us about nodes, if there are 3 nodes we will need 3 links to connect all of them. If we have 5 nodes then we will need 10 links. How about if we have 25 nodes, how many links do we need? The answer is a function like this:  where L is the number of links, and n is the number of nodes.

He also told us the differences between a hub and a switch.

And about the satellite, he taught us the advantages and disadvantages. The advantages of a satellite are its ability of long distance connections, and it can withstand the earthquake. The disadvantages are the cost that is very expensive, and the delay impact because of the long distance.

Next discussion is about network architecture models, which consist of 2 models, they are: the classical OSI model, and the Internet model. There are 7 layers of OSI model: Application (a layer where the application using the network resides), Presentation (perform miscellaneous functions for presents data package properly to sender / receiver), Session (establish sessions between applications), Transport (provides an end-to-end error free network connection), Network (create, maintain, and end network connections), Data link (taking data and transforming it into a frame), and Physical (handle transmission of bits over communication channel). On the other hand, there are 4 layers in the Internet model, they are Application layer, Transport layer, Network layer, and Interface layer.

That’s all for Data Communications and Computer Networks class.

(source: slide from Data Communications and Computer Networks class

15.02.2012

Today’s class is software engineering process and management.

I learned about software engineering method, which is a structured approach to software development to facilitate the production of high-quality software in a cost-effective way.

The lecturer told us the purpose of software engineering, the purpose is to build a software (human thinking) to deliver a quality product on time, on budget, and to fulfil users’ real need. We need efforts to achieve that, and the efforts is through process and management. Based on what the lecturer’s words, software is not only in a form of code, but also its file, database, architecture, documentations, and so on. We will use some tools in software engineering, such as Oracle software tool, and rational rose software tool. A software production is a process from product specification stage, until the maintenance stage, while software engineering method is a systematic approach in a software development.

A framework is a high level explanation about list of works that have to be done, but not mention about how’s the sequence. The methodology, then, will describe how it will be done. CMMI (Capability Maturity Model) framework is a framework for continuous capability improvement. At last, the class talks about myth and reality in term of software engineering. A myth here is something that believed first by people, while the reality is not always the same with the myth. Although we already have some standard in the myth, we still need further adjustment when it comes to the reality. For example, we have myth that says that if our project is late, then we can hire additional worker as a solution. The reality in software engineering is that adding more people into the project will not make the progress faster, in contrary it will make it slower because we have to explain everything about the project from the start once again, to that new peoples.

That’s all from PM-RPL class.

(sources: my notes and slide from class)

16.02.2012

Today’s class is Information System Design. This class mainly talks about RUP (Rational Unified Process).

First of all, we discuss about the components of a process, the components are what (the artefact), how (the activity such as concept and guideline), who (the worker), when/sequence. So we can say that a process defines who is doing what, when, and how to reach a certain goal. Each individual can have double role, for instance a system analyst can also become an implementer. High quality software should fulfil all the end users needs on time and on budget. We can get an effective process from the collection of best practices with contribution from variety sources.

A characteristic of Unified Process is that it implements an iterative and incremental development process. Incremental means we didn’t develop all at once, but step by step on each iteration. From basic, then we add the feature/function, until the last iteration that already consists of all the user’s needs.

RUP is a collection of best practices, a process product, a process framework, and also a process model. Because RUP is a very complete framework, we don’t usually utilize all the modules. We only use its subset, the features that relevant to our project.

RUP has 4 roles: provides guidance for us to divide our time activities, it also decides which and when an artefact has to be developed, it direct the tasks of individual developers and the team as a whole, and the last one is that it offer criteria for monitoring and measuring the project’s product and activities. RUP has 4 phases: Inception, Elaboration, Construction, and Transition. RUP describes how to implement the 6 best practices for software development. Those best practices are to develop a software iteratively, then manage the requirements, use component architectures, model visually, verify quality, and finally to control changes. Other features of RUP are use-case driven development, process configuration, and integrated tools support.

In software engineering, we have a kind of jargon that says about how we feel we’ve done our work at 80% level, but the remaining 20% seems need efforts as high as the 80% did.

And that’s all for today’s class

(source: my notes and slide from class)