CS507 Information Systems Solved Subjective Short Questions Answers from Text Book (chapter 4 - 10)
The organization is seen as a closed, mechanical system. The emphasis is on design of a system and managing for efficiency. The five functions of managers are planning, organizing, coordinating, deciding, and controlling.
The key ideas are that organizations are seen as open, biological organisms like a cell, or animal. The organization’s survival depends on its ability to adapt to the environment and to ensure that all the parts are working together. As part of the effort to be successful, the members of the organization are satisfied and functioning well. The characteristics that are emphasized by the behavioral school are highly fragmented activities, changing activities rapidly, spending time pursuing personal goals, and shying away from sweeping policy decisions.
They can support the liaison roles of managers through e-mail, and the information roles of nerve center, disseminator, spokesman, and resource allocator. They are probably strongest at the nerve center, resource allocator, and spokesman roles. They are particularly weak at figurehead, leader, disturbance handler, and negotiator roles.
Wrapp closely examined the characteristics of managerial decisions. He found that good managers rarely make forthright policy decisions, preferring to devote more time and energy to operational decisions. Managers tended not to set overall organizational goals but instead provided the organization with a general sense of direction. In this manner mangers maintain visibility without being forced into a policy straightjacket.
Kotter's research describes how managers get their work done. They devote considerable time to establishing personal agendas and short and long-term goals. They spend a great deal of time building interpersonal networks throughout the organization, cultivating personal contacts and relationships. Managers then use these personal networks to execute their personal agendas. Computerized information systems that facilitate communication and networking help support these activities. Especially useful are electronic mail systems, voice messaging, and teleconferencing facilities. The chapter also notes the value of systems that provide instant access to management-level information on sales performance and external data such as currency and commodity values. Contrary to the classical description, even senior managers shied away from grand sweeping decisions in favor of "muddling through." Contemporary managers prefer to implement plans piece by piece without drawing attention to an explicit comprehensive design.
The organization is a knowing, sentient organism. Organizations seek to make sense out of their environments and can “learn and “know.” The efficiency and effectiveness of the organization depend on its ability to be correct in its learning and judgments, as well as the organization’s ability to gather and disseminate information. The manager’s role is to use his or her ability to properly define the situation of the organization and to build the information and knowledge infrastructure of the organization.
Unstructured decisions are non-routine decisions in which the decision maker must provide judgment and evaluations for which there is no standard procedure. Examples are: Deciding to start a new division, a new marketing campaign, a decision to invest in a country.
Structured decisions are repetitive and routine with standard procedures for solutions. Examples would be: product mix, plant scheduling, facility layout.
The four kinds of computer-based information systems that support decisions (from lowest to highest) are:
Transaction processing systems (TPS
Management information systems (MIS)
Decision support systems (DSS)
Executive support systems (ESS)
Simon's four stages of decision making are:
Implications for information system design are that decision-making is a very complex process, even when a rational model is assumed. Decision situations are high variable, depending on individual frame of reference, nature of goals and types of decision-makers. Information systems are more useful for supporting the decision-making process than for making decisions in place of people. Therefore, IS design should be flexible, with many options for handling data, evaluating information and supporting a variety of decision styles and skills. IS should, wherever appropriate, use powerful models for evaluating data with the ability to track many alternatives and consequences.
The subsection of 4.4, Organizational Models of Decision Making summarizes the four “models of organizational decision making.” The four models are:
1) Rational model - assumes that human and organizational behavior is based in value-maximizing calculation within certain constraints (profit maximization or expected utility maximization in decision theory).
2) Bureaucratic models - the most important goal is the preservation of the organization, with reduction of uncertainty a major goal. Organizations following this model change incrementally.
3) Political model - what occurs in the organization is the result of power relations and political interest groups.
4) Garbage can model - assumes that organizations are not rational, and decisions are accidents.
Managers now have to manage entire processes as in the Lantech Window on Organization in Chapter 3. Managers have to treat the knowledge and core competencies of the organization as the key assets. Further, managers have to adapt to current regulatory rules and social mores. Managers are responsible for enabling employees to meet their goals and the organization’s.
Information technology allows the reengineering of business processes and management of workflow. Information systems allow managers to share information more easily and learn the state of the world more easily.
Information cannot be used effectively if it is stored in a unorganized, inflexible manner. Without proper file management, it may be difficult and even impossible to extract information from an automated system. File management must also be flexible enough to accommodate new pieces of information or to combine different pieces of information in changing ways. When computer files are poorly managed, poor performance, high costs and minimal flexibility will result.
An index, like an index in a book, provides a means of finding a specific record's storage location. The index is a list of the key field of each record and the address where the record is stored.
Key fields provide a means of uniquely identifying records, such as a social security number or a product number. Being unique, the key field is the key to an index table which associates the storage address of each record with its key.
The indexed sequential access method (ISAM) is a way of storing data records on a physical storage device in sequential order for sequential processing (such as in payroll applications). However, ISAM also allows any specific record to be directly accessed without searching through the file sequentially by using the record's key field to find its storage address in an index.
The direct file access method does not store the records in sequential order, as with ISAM. It uses a key field to determine the location of each record. However, rather than carrying that location in an index, the location is calculated each time using an algorithm that translates the key field directly into the record's physical storage address.
Data redundancy is the presence of duplicate data in multiple data files. In this situation confusion results because the data can have different meanings in different files. Program-data dependence is the tight relationship between data stored in files and the specific programs required to update and maintain those files. This dependency is very inefficient, resulting in the need to make changes in many programs when a common piece of data--such as the zip code size--changes. Lack of flexibility refers to the fact that it is very difficult to create new reports from the data when needed. Ad hoc reports are impossible; a new report could require several weeks work by more than one programmer and the creation of intermediate files to combine data from disparate files. Poor security is a problem resulting from the lack of control over the data because it is so widespread. Sharing of data can be virtually impossible because it is distributed into so many different files around the organization.
A database is a collection of data organized to service many applications efficiently by centralizing the data and minimizing redundant data. A database management system is special software that permits an organization to centralize data, manage it efficiently, and provide access to the stored data by application programs.
The three components of a database management system (DBMS) are:
A logical view of data is the way data is perceived by end users or business specialists. A physical view of data is the way the data are actually organized and structured on physical storage media.
The hierarchical database model stores data logically in a vertical hierarchy resembling a tree-like structure. An upper record is connected logically to a lower record in a parent-child relationship. A parent segment can have more than one child but a child can only have one parent. Hierarchical DBMS are good for treating one-to-many relationships. They can store large numbers of segments and process information efficiently, but they can only deliver information if a request follows the linkages of the hierarchy. Their disadvantages are their low user-friendliness, inflexibility and complexity of programming. They are good for high volume rapid response systems, such as airline reservation systems.
The network model stores data logically in a structure that permits many-to-many relationships. Through extensive use of pointers, a child segment can have more than one parent. Network DBMS reduce redundancy and, like hierarchical databases, they process information efficiently. However, they too are inflexible and are very complex to maintain and program.
The relational structure overcomes many of the limitations of these other structures. Data are organized into two-dimensional tables, each of which can be considered a file. The relational model can relate any piece of information in one file to any piece in another file as long as the two tables share a common data element (such as an employee number). Because relational DBMS can easily combine information from different sources, they are more flexible than the other DBMS structures. Access paths to data are not pre-specified, so that they can easily respond to ad-hoc inquiries with less extensive programming. The main problem with relational DBMS is poor processing efficiency. Response time can be very slow if large numbers of accesses to data are required to select, join and extract data from tables. Developments in relational technology are starting to overcome this problem, such as indexing.
Normalization is to streamline the database design to remove redundant data such as repeating groups. A database which is not normalized will have inefficient queries and will delete information when it should not or update only part of the information on a person.
A distributed database is one that is partitioned, or distributed among more than one physical location. Parts of the database are stored in one location and other parts are stored and maintained in other locations. One main central database can be partitioned into multiple local databases. These databases can be updated locally and later justified with the central database. Alternatively, the central database can be duplicated at various remote locations. Another possibility is to maintain a central index and have complete records stored at local levels.
Distributed data processing means using microcomputers, minicomputers and small mainframes at remote locations to process information in a central database rather than relying entirely on a central mainframe. However, unless the database itself is distributed, the data are still stored in one central location.
Traditional databases store only homogeneous data that can be easily structured into predefined data fields and records. They are not well suited for handling other types of data such as procedures or graphics. Object-oriented databases store data and procedures together as objects. Hypermedia databases store chunks of information in linked nodes. These nodes can contain text, graphics, sound, full-motion video or executable computer programs. These databases will be less structured than in traditional DBMS and contain a wider array of data. The nodes of a hypermedia database can be linked in any kind of relationship established by the author.
On-line analytical processing and multidimensional data analysis allow the analysis of large volumes of data from many perspectives, for example, sales by item by department by store by region, in order to find patterns in the data. Such patterns are difficult to find with normal database methods, which is why a data warehouse and data mining are usually parts of OLAP.
A data warehouse is a database with archival, querying and data exploring tools (i.e., statistical tools) for storing historical and current data of potential interest to managers throughout the organization and from external sources (e.g. competitor sales or market share). The data originate in many of the operational areas and are copied into the data warehouse as often as needed. Date warehouses support looking at the data of the organization through many views or directions. To complete the Vegamatic (TM) analogy used earlier, a data warehouse allows managers to look at products by customer by year by salesperson -- different “slices” of the data. Normal operational databases don’t permit such different views or slices of the data.
The critical elements in a successful database environment are:
Answers will vary with individual students. Some of the major management challenges in building a database environment are:
Deregulation of telecommunications means that organizations do not need to rely on the telephone company for telecommunications services and devices. Organizations can choose from many different companies and services selling telecommunications services and equipment. To use telecommunications wisely, organizations must develop expertise in telecommunications and may need to employ their own telecommunications specialists. Managers must know alternative telecommunications technologies and systems and the costs, benefits and capabilities of various technologies, as well as a method for determining the organization's telecommunications requirements.
A telecommunications system is a collection of compatible hardware and software arranged to communicate information--text, graphic images, voice or video--from one location to another. The principal functions of all telecommunications systems are:
The components of a telecommunications system are:
An analog signal is represented by a continuous wave which passes through a communications medium. A digital signal consists of separate discrete waves.
Medium Speed Cost
Twisted wire 300 BPS-- 10 MBPS Low
Microwave 256 KBPS--100 MBPS
Satellite 256 KBPS--100 MBPS
Coaxial cable 56 KBPS--200 MBPS
Fiber optic cable 500 KBPS-- 10 GBPS High
Bandwidth is the range of frequency (difference between the highest frequency and the lowest frequency) that can be accommodated on a particular telecommunications medium. The greater the range of frequencies that the telecommunications transmission medium can accommodate, the greater the medium's telecommunications transmission capacity.
Asynchronous transmission transmits one character or byte at a time over a line. Each string of bits comprising a character is framed by control bits. Synchronous transmission sends characters in blocks, framed by header and trailer bytes called flags. Synchronous transmission is used for transmitting large volumes of data at high speeds because groups of characters can be transmitted more rapidly as blocks with no start and stop bits between characters.
In simplex transmission, data must always travel in only one direction. Half-duplex transmission allows two-way flow of data, but data can only travel in one direction at a time. Full-duplex transmission can send data in both directions simultaneously.
1) Star network - involves a central host computer connected to a number of smaller computers or terminals. All communication between points in the network must pass through the host computer.
2) Bus network - links a number of computers by a single loop circuit made of twisted wire, cable or optical fiber. All messages are transmitted to the entire network and can travel in both directions along the cable. There is no need to have a host computer controlling the network.
3) Ring network - similar to a bus network except that the connecting wire, cable or optical fiber forms a ring. Data are passed along the ring from one computer to another, flowing in a single direction, and the network does not rely on a central host computer.
The PBX (private branch exchange) and the LAN (local area network) are similar in that they both serve a restricted setting of several hundred feet and both use the same kind of telecommunications media (twisted wire, coaxial cable or fiber optics). However, the PBX utilizes the firm's own telephone system, is based on the firm's internal telephone network and requires no special wiring. A LAN is more general purpose and is not tied to a telephone network, but requires special wiring, installed by the organization.
A wide-area network (WAN) spans a broad geographical distance, ranging from several miles to the span of an entire continent. WANs are provided by common carriers, companies such as AT&T and MCI which are licensed by the government to provide communications services to the public. With a WAN the user is responsible for establishing the most efficient routing of messages, error checking, editing, developing protocols and managing telecommunications.
Telecommunications applications that can provide strategic benefits to businesses include:
The major components of a telecommunications plan are:
The telecommunications plan will also need to address specific network requirements concerning: