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Thursday, December 9, 2010

UML

SYSTEM ANALYSIS AND DESIGN
QUESTION 1
The University is considering a new system to speed up the student registration process. As a systems analyst, you are asked to develop a plan for fact finding.
(a) List all the information gathering techniques that all systems analysts must be able to use.
(b) Explain any three of the techniques listed.
(c) Explain the criteria for selecting a given technique.

Solution
(a) Interviews
Questionnaires
Observation
JAD (joint application design)
Document Analysis

(b) (i)Questionnaires
This is the mode of gathering data from sampled participants in order to understand an existing system or know the expectations of a new one. The researcher sets off by firstly carefully designing the questions which would best reveal the desired information he so desires.

He, then, goes ahead to administer these questionnaires to his sampled participants and makes sure that they answer them. This is done through follow-ups. But care should be taken that the one administering the questionnaires has good inter-personal skills in order to have a successful survey of opinions.

(ii) Interviews
This technique also involves gathering information from people though in this sense, one would have to talk to his interviewees and ask them relevant and well-crafted questions in order to receive relevant answers. The interviewer is to be able to respectfully steer the conversation/interview to areas of his interest while sifting through all that the interviewee would say.
To engage in a successful interview, the interviewer must first select his interviewees (people he thinks are in a position to know what he needs to know). He can then proceed to formulate concise and relevant questions which he would use to both prepare and conduct the actual interview. It is necessary that after the interview, there be a follow-up by the interviewer in a bid to re-gather vital information interviewees might have forgotten to share, and also probably give them feed-back on the previous interviews.

(iii) Observation
Because people cannot always remember everything they do and the fact that they tend to act differently from their usual selves when they know they are being watched, there is need to independently verify information gotten from them through different methods. Observation is that technique of gathering information without the involved parties becoming aware of it. The Observer should make sure to be discrete, unpredictable and attentive to everything that happens regarding his subjects so that he can read trends which can be compared with information gathered through other sources.

(c) When choosing an information gathering technique, one should take into consideration
1. What type of information is being sought?
2. What is the gravity of the information being sought?
3. What is the scope of the information being sought?
4. Which technique can give corroborated information?
5. Is there need for users to be involved or they can circumvented?
6. What is the comparative cost in getting relevant information through the use of any given technique?

QUESTION 2
(a) What is UML?
It is the abbreviation for Unified Modelling Language. Since a model abstracts the essential details of the underlying problem from its usually complicated real world, it is necessary that there be a standard set of tools which can be used to organize/develop these models so as to allow many categories of people understand them.
Explain the use of the following diagrams:
(i) Use Case diagram:
They are UML diagrams that describe what a system does from the stand-point of an external observer. This is gotten from the fact that a use case, per se, is a summary of all the scenarios for a single task. It is made up of an actor (the user of the system), a use case (what the actor uses the system for) and an association (the actor’s relation to the use case). Thus a use case diagram is a collection of actors, use cases and their relative associations.
They are useful in that they, primarily, help in determining system requirements since new cases may elicit new system requirements as the diagram takes shape. They also aid communication between system developers and clients through the use of relatively simplified diagrammatic notation. Finally, they are useful in generating test cases in that the associated scenarios give a perfect collection of test cases for the system.

(ii) Class Diagrams:
A class diagram gives an overview of a system by showing its classes and the relationships among them. Class diagrams are static in that they display what interacts but not what happens when they do interact. This is from the background that a class is a template for merging attributes and behaviours into a single distinct entity, an object.






Friday, May 7, 2010

How IT can give your company competitive advantage

QUESTION
As an IT manager, advise your company on some of the top security issues and prepare a document to advise them on the benefits which can be achieved with the introduction of IT to create competitive advantage. Pick a case study area and base everything on it. Indicate the company and state what they do.

COMPANY PROFILE

PJEF Company Limited is a magazine printing and publishing company headquartered in Accra, with branches in Kumasi, Sunyani and Tamale. It has an online presence on the internet through their website where their publications can be perused and bought. This aspect is handled by the publishing and IT departments. It has a centralised authority structure. Though quite relatively modern, PJEF Co. Ltd uses off-the-shelf software, and an open internet system to network the different branches. Some very important documents are still kept on paper while the company puts no clear restriction on data access, especially within the proof reading department which happens to have developed a sort of departmental database which is at times utilised by the other departments. The Management board recently has tasked the IT department to identify some of the issues which adversely affect the efficient operation of the company. As the manager of the tasked department, the following are my findings

SECURITY RISKS AT PJEF CO. LTD.

As per the mandate of the Management Board, in my capacity as the IT manager of this company, I have carried out the authorised assessment of the operational IT risks of this company and the following form some of my major findings.
a. The use of only off-the-shelf software: As a printing and publishing company, PJEF cannot continue to rely on only off-the-shelf software to run its operations. So doing exposes the company to a lot of disadvantages such as making it easier for thieves to steal and pirate printing material. Again the absence of customised software such design software which is specifically written to suit the needs and operations of this company makes it very tedious for the design, typesetting and desktop publishing department to create a style which sets PJEF apart from other publishing houses.
b. Use of Open internet connectivity: Being a fast growing and quickly spreading company, PJEF cannot continue to use the open insecure internet as the means of networking its branches. The tendency for data loss/theft and corruption, not to mention the possibility of malicious attacks on PJEF corporate systems are real threats to the very operation of the company. Also, as a commercial entity which prides itself in quality work, it becomes a matter of competitive disadvantage while it does not speak well of the company to have in place no mechanism to protect the hard work of its valued clients, namely the signed authors.
c. On-site back-up: As a matter of great operational risk is the issue of on-site back-up. Currently, the IT department has no means of directly and simultaneously backing up all company data files off-site. The current system where data is backed up on site and later manually transferred to an off site location has a number of disadvantages such as the possibility of loss of limited but critical data and the possibility that due to human error may cause data not to be backed up at all, as indeed happened in the near fatal incident involving the PJEF and the author of a textbook. The current method of backing up leaves the company open to viral attack and data corruption since data transfer is manually handled.
d. Documentation of Important material on paper: The practice whereby the company still keeps important material on paper without making electronic copies could be very costly should there be a fire outbreak or even pest attack. While the practice of keeping such documents in a combination safe is quite laudable for keeping burglars at bay, it is quite insufficient to keep fire and other hazards out.
e. Poor database management: The Company has no database which makes it quite cumbersome when managing data inflow and access. The departmental database instituted by one of the departments is full of redundant data. The absence of an up-to-date database impedes managerial decision making, gives no clear picture of company performance and virtually creates a barrier between related departments.
f. Easy Access to Company Data: Going round with respect to finding out some of the security risks facing the company, I stumbled upon one very important issue, namely the easy nature in which data is accessed in this company. There appears to be no access restriction on some data, making such data easily accessible to almost everyone and thus vulnerable to theft, change or deletion. The practice whereby people can easily insert their personal external storage devices into the company computer system without having them scanned for viruses and then issued with clearances to use such secondary storage media could cause complete system failure should a very dangerous virus find its way into the company system.
The above are by no means the end of the list but they form the core of the security threats which the company faces. I will now go on to recommend ways in which the company can solve the problems enumerated above and thus increase its competitive advantage by introducing IT.
RECOMMENDATIONS
• The company should consider diversifying its operations by incorporating custom built and customised software into its computer systems. As a printing and publishing company which publishes both for the physical and online market, it gives the company some competitive edge when it does everything possible to produce products which are different from what everyone else in the business is producing. Since customised software is practically written to suit the preferred taste and operations of the one who orders it, unlike commercialised ones, it gives the company a very important tool to produce products which cannot be made anywhere else apart from PJEF.
• Though the company publishes on its internet website, it should consider using the many social network sites such as facebook, twitter, hi5, tagged, badoo, perfspot, myspace, etc. to increase awareness of its products and thus increase its customer base. When people on these sites are able to appreciate the good work which this company produces, the stage is set for us to take care of big printing orders which would arrive from almost every corner of the world. To add, the IT department should be resourced to help the relevant departments create a formidable online presence through serious online advertising campaigns.
But this should not draw away from the fact that the company needs to develop a better internal network purposely for coordination between the different branches. If this is done, data flow and sharing will be faster, safer and more reliable.
• As a matter of urgency, it is my recommendation that the company proceeds to make provisions for automated off-site back up of its data. This will forestall the loss, possible delays or corruption of company data. This will make the company appear more reliable to potential clients who would rest assured that their work will be finished on time any catastrophe notwithstanding.
• The company needs to immediately begin the process of converting into electronic format all important company documents. With current technology, documents which come in electronic formats are easier to store protect and transfer than their hardcopy counterparts. Watermarks can also be embedded within such documents as a seal of authenticity while they can be copy protected, write protected or even set to track changes made to it at what time. These attributes of the electronic file help the company to better protect its documents from corporate rivals.
• There needs to be an up-to-date database put in place with its requisite data access protocol. With the introduction of a regularly updated database, different departments within the company can have access to relevant data and hence increase efficiency and productivity, cutting down the time used to search for some particular data. Sensitive data will also be protected from unauthorised access leading to a generally confident working environment.
• Finally, the company should make it a policy not to allow personal secondary devices to be used on company computers except they have been scanned for any malicious software and after they have been used on the company computer if any company documents have been copied. In this quest, the system administrator should be vigilant in his work and flag any potential unauthorised system access and usage.

Thursday, March 4, 2010

types of OS

The computer industry, complicated and ever changing as it is, can boast of quite a number of Operating systems (OS), system software that enables communication between computer hardware and any other software that might be installed on the computer system. An OS type is defined by how it relates to the time factor, functionality (tasking), number of simultaneous users and level of manipulation. The above noted, we could speak of OS types such as
• Real-time Operating Systems
• Multi-user and Single user Operating systems
• Multi-tasking and single-tasking Operating systems
• Distributed Operated systems
• Embedded Operating system
It should however be noted that a particular OS may employ characteristics of two or more types of OS to maximise functionality and portability. At this point I would opt to write about multi-user operating systems.
A multi-user operating system ensures that more than one user operates the computer system at any one particular time. Resources of the computer system are so managed in a way that allows for speedy execution of operations by any one user in a way that gives an individual user the impression that he/she is the only one using the computer system at that particular time.
From the above, one is correct to bear in mind that for such an OS to work properly, the system must have good computing speed to ensure maximum computer time for each individual user, possess enough system memory to store the operations of each user, proper networking of the workstations involved (though some systems have done away with the use of workstations and instead operates using user accounts existing on the same system).
Use of a multi-user OS comes with a number of advantages such as reduction in hardware and software cost through shared resources, better system control through use of usernames and passwords that improves system security, though system breach becomes far more costly.
To end, it is worth mentioning that many of the popular operating systems available today are examples of multi-user OS. These include the Apple’s Mac OS, Microsoft’s Windows and almost all the UNIX distributions including Linux, Sun’s Solaris, etc.









BIBLIOGRAPHY
Slater, Robert, Portraits in Silicon, MIT Press, Cambridge, 1992.
http://www.computerhope.com/os.htm, 11-02-2010
http://wiki.answers.com/Q/What_are_the_four_types_of_operating_system_according_to_category, 11-02-2010
http://computer.howstuffworks.com/operating-system3.htm, 11-02-2010

UNIX

Starting as a project by two Bell laboratories researchers, Dennis Ritchie and Kenneth Thompson, who simply wanted to make computing easier for themselves, the UNIX gradually became industry standard around the 1960s up till date. This was against the backdrop that the two researchers wanted an operating system that was easier, safer and user friendlier than Multics, the operating system which was being used at the time by Bell Laboratories. Though it never could topple Bill Gate’s MS-DOS and later Windows, it had by the 1980s become the most transported operating system used by large and middle-sized computers. Written in C, UNIX was developed by AT&T.
The UNIX OS can be said to have been a major player in the development of the internet due to its unique environment and server-client model. Its popularity also arose principally from the fact that it was freely distributed. Currently, many UNIX derivatives are distributed both freely and commercially.
Made up of the Kernel, file system and the command-line interface called the shell, UNIX boasts of more than 600 commands enabling users to manipulate data in any conceivable way. The above noted, UNIX has many advantages that makes it the best operating system to use.
Regarding cost, UNIX can be said to be very cost effective since it exists in both freeware and commercial distributions. This makes it better than the totally commercialised operating systems that exist today, for instance windows.
In matters of portability, none compares with the UNIX system. Because of the many distributions of different versions of UNIX, such as Linux (which also comes in many distributions) Sun’s Solaris, etc, one can easily use programs designed for one distribution in other distributions and not have to worry about efficiency. Currently, with the embedding of winetools in the source code of many UNIX distributions, many application software developed especially for the windows platform can now be used by UNIX users.
Because UNIX is freeware, it makes available source codes to people who intend to adapt them for personal use or in the name of education. This cannot be said for licensed OS like Windows which makes it a crime to edit its (window’s) source code. Because of that, one can always expect better output from the UNIX because there are so many people working to make it better to use.
Security is also better in a UNIX system than many other operating systems. Because of the compact layers of the UNIX kernel and the command-line Shell which requires that only the administrator with Super User (SU) privileges can change system parameters, it is very difficult to encounter security breaches from malware and unauthorised access.
Finally, it is worth noting that gone are the days when the UNIX shell scared a lot of people from using UNIX. Now with the incorporation of the motif GUI in many UNIX distributions, including Linux, it has become user friendly yet maintaining its security. No wonder the increasing popularity UNIX distributions, such as Linux, enjoy presently.
BIBLIOGRAPHY

Slater, Robert, Portraits in Silicon, The MIT Press, Cambridge, 1992.

http://en.wikipedia.org/wiki/Unix, 11-02-2010
http://www.unix.org/what_is_unix.html The Open Group, 28 December 2003, 11-02 -2010
http://www.unix.org/whitepapers/uos.pdf, the Open Group, 11-02-2010

of Hobbes and Quarrels

Q3: Discuss the principal causes of quarrel in every society as proposed by Thomas Hobbes
Thomas Hobbes is of the view that man is exclusively selfish in all his actions and is not likely to perform any action if such an action will be of no benefit to him. It is on this premise that Hobbes begins his discussion on the causes of quarrel in the human society.
It is worth noting that in Hobbes’ view, there is in practice nothing which is objectively good or bad, but that there are only things which a person desires and that which he averts, representing good and bad, respectively.
Moving on to the causes of quarrel, Hobbes gives three main reasons why there is conflict in society, namely competition, diffidence and glory. But it worth noting that the proper context where the three causes promote conflict is found in Hobbes’ psychological theory where he states that
a. the individual is psychologically selfish,
b. the individual’s greatest desire is self preservation
c. the individual’s greatest aversion is death.
Again it is worth considering the two laws of nature (namely seeking peace in order to follow it and defending oneself by all means) and how they affect the individual’s desire for self-preservation and his aversion of death.
Considering competition as a cause of quarrel, Hobbes makes it known that nature has made all people equal in the powers they need to exist. But there is the selfish inclination within man to try to maximize his happiness, which is nothing else than the level of success one has in self-preservation. Hence he invades others for gain, leading to quarrel.
For reasons of safety, an individual may be forced to confront others. This is called diffidence. Should any threat, imagined or real, arise to cause fear in an individual’s desire to maximize his happiness, he is forced to counter that threat through any means necessary, hence quarrel with the object of his aversion.
Finally, because of man’s selfishness, he tries to assert himself over others. He thus looks for means to achieve glory which is nothing else but quest for reputation. When and individual does not wish to remain on equal terms with others, he resorts to all manner of actions to assert himself over them. Thus glory becomes a cause of quarrel taking into account that man is naturally selfish.
In conclusion, without the presence of a sovereign who would provide the needed balance to every individual’s desire, the probability is high that every person will quarrel with his neighbour, given that confrontations may arise out of desire for self preservation, aversion to fear in favour of safety or to seek glory.

of pure silicon and diodes

  1. Pure silicon is not a conductor because in its pure state its electrons are bonded tightly with the electrons of other neighbouring silicon atoms in such a way that it requires a relatively large increase in energy levels to cause electrons to break from the valence band into the conduction band.

  1. When silicon is doped with phosphorus, the result would be that an excess of one electron is created on the valence band of the doped silicon atom. Since the valence band of an atom takes up to eight (8) electrons, there would exist one free moving electron which can easily jump into the conduction band, thus constituting flow of electrical current.
  2. The main difference between a P-type silicon and an N-type silicon exists in what material was used to dope the silicon. Should the silicon undergo a Trivalent doping, using an element with a valence band consisting of 3 electrons (eg boron) there would exist one empty spot on the shell after the two elements are bonded thus leading to the formation of a P-type silicon. It is P-type (positive) because it lacks one more electron to complete its valence band.However should silicon be doped with a pentavalent element, (thus an element with 5 electrons on its valence band) there would exist an excess electron on the valence shell after the two elements bond. This excess electron, which is free moving, thus has the capacity to jump the gap into the conduction band.

  3. A diode, being a device which allows electric current to flow in one direction is made up of a P-type and an N-type silicon arranged adjacent each other, leaving a thin film of space called the depletion region connected to an energy source. It is in the arrangement of the energy source in the circuit which dictates in which direction current flows.

    In a forward biased diode, there exists a positive voltage across the diode from the P to N type silicon. This enables the diode to act like a good conductor hence allowing current to flow in one direction.

    However, when the polarity in the energy source is changed so that there is almost no flow of current then one has a reverse-biased diode. This causes the diode to become almost non-conducting and measures a large amount of voltage across the devise.

A very brief examination of Hobbes' state of Nature

Q2: Examine the “state of nature” in the context of Thomas Hobbes’ view.
The State of Nature is, in Hobbes’ view, the state in which man lived with other men before the emergence of the civil society or the commonwealth. He, however, lays no claim on the actual historical existence of a state of nature, but rather that the state of nature exists in any place or time where civil society is not functioning.
The workings of the state of nature can be understood in its proper context when one takes into account the psychological theory of Hobbes which makes the following assertions, namely, that man is psychologically egoistic and would do nothing except from selfish motives; that there exists no objective good or bad except those things a person desires, which he considers good and those things he averts which he considers bad and those things which he has contempt for, which he considers vile; that the highest desire of man is self-preservation and his worst aversion is death and; that all people are equal in their natural means of attaining the objects of their desire, and this, he terms power . Thus, Hobbes makes the claim that in the state of nature, happiness is judged only by the amount of success he has in pursuing the object of his primary desire, namely, self preservation.
Again, Hobbes makes the claim that morality is nothing apart from the will of the sovereign. Thus, if there exists no sovereign to promulgate laws for the general conduct of the people, there would exist no ethical code, hence no morality. One could even make the concession that the only law of morality is that of self-preservation which necessitates the use of all measures to ensure that the individual protects him/herself from any and all things which he considers a threat to his wellbeing irrespective of how negatively such measures may affect others.
From the above, it is perceived that in the state of nature, conflict is a common feature. This stems from the fact that all individuals are equipped with the same natural powers to achieve self preservation. But since every individual is selfish and not restrained by any central authority though each has to protect himself using the same powers, they are each equally capable of inflicting injury on their neighbours, hence conflicts.
Finally, in the state of nature, there is anarchy. Morality is primarily dictated by the desire for self-preservation which is itself a product of vital and voluntary motion. In the absence of a sovereign, individuals lack that awareness which reason imparts on their actions. Thus, in Hobbes’ view, without any law to restrain people’s actions there would be total lawlessness since each person would only act in order to maximize happiness .
BIBLIOGRAPHY
BONEVAC, Daniel, Today’s Moral Issues, (3rd ed.), Mayfield Publishing Company, California, 1999.
KOLAK, Daniel, Questioning Matters, Mayfield Publishing Company, California, 2000.
WHITE, James E., Contemporary Moral Problems, (5th ed.) West Publishing Company, New York, 1997.