Previous Definition
Variable costs are those incurred in direct proportion to the number of units produced.For example,the cost of raw materials is directly proportional to how many intake manifolds are produced,and therefore to how many 3,8-liter V6 engines are made.
(Kalpakjian S. , Schmid S.R. , Manufacturing Engineering and Technology, p.215)
New Definiton (Better)
A variable cost is a cost that varies, in total, in direct proportion to changes in the level of activity. The activity can be expressed in many ways, such as units produced, units sold, miles driven, beds occupied, lines of print, hours worked, and so forth. A good example of a variable cost is direct materials. The cost of direct materials used during a period will vary, in total, in direct proportion to the number of units that are produced. To illustrate this idea, consider the Saturn Division of GM . Each auto requires one battery. As the output of autos increases and decreases, the number of batteries used will increase and decrease proportionately. If auto production goes up 10%, then the number of batteries used will also go up 10%.
( Garrison, Noreen, Brewer, Managerial Accounting and Cost Concept, p.45-46 )
2. Indirect-Labor Cost (Management)
There is no previous definition.
Definition
Indirect labor cost is the labor costs of janitors, supervisors, materials handlers, and other factory workers that
cannot be conveniently traced to particular products.
( Garrison, Noreen, Brewer, Managerial Accounting and Cost Concept, p.34 )
3. Life Cycle Engineering (Design)
Previous Definition (Better)
Concerned with enviromental factors as in life cycle assesment, Life cycle engineering deals in greater depth with design, optimization, and various technical considerations regarding each component of a product or process life cycle. A major aim of life cycle engineering is to consider reusing and recycling the components of a product from the earliest stage of discussing and considering the product design.
Although life cycle analysis and engineering are comprehensive and powerful tools, their implementation can be costly, challenging, and time consuming. This is largely because of uncertainities in the input data and the time required to gather reliable data to properly assess the often complex interrelationships among various components of the whole system. Various software is being developed to expedite these analyses, particularly in the chemical and process industries because of the higher potential for enviromental damage in their operations.
(Kalpakjian, Smith; Manufacturing Engineering and Technology,p. 1245)
New Definition
Life-cycle engineering seeks to incorporate various product life-cycle values into the early stages of design. These values include functional performance, manufacturability, serviceability, and environmental impact.
( K. Ishii, Life-Cycle Engineering Design, p. iv )
4. Computer-Aided Software Engineering (Design)
Previous Definition
Computer-aided sorfware engineering (CASE) encompasses computer-based procedures, techniques, and tools which can be used to develop, maintain, and reengineer software. CASE is to the sorfware engineer as computer-aided design/computer aided manufacturing (CAD/CAM) (4. v.) is to the mechanical engineer and computer-aided electrical engineering (CAEE) is to the electrical engineer. Although the variety of technological alternatives can be bewildering, the concepts of CASE provide a commonsense approach to engineering quality software more productively.
The application of CASE is intended to allow teams of software engineers to produce softwarethat:
* meets business and system requirements
* is completed within a predictable Schedule
* is available within budget guidelines
* allows for easy maintenance and enhancement
(David Sharon, Computer Aided Software Engineering, p. 278)
New Definition (Better)
Computer-Aided Software Engineering (CASE) is the integration of software-based modeling tools into the software development process. Analysis and design methodologies and modeling notations were developed to formalize the softwareengineering process; CASE tools automate that process by assisting in each step. Some types of CASE tools are analysis and design tools, automated code generation tools, and software testing tools. Analysis and design tools aid in the creation of diagrams and project documentation. Automated code generation assists in the implementation phases. Testing tools lead to a more thorough evaluation of an application. Table 6-1 provides a chronological list of CASE tool development.
Early CASE tools were used to create project documentation and to assist in the creation of analysis and design diagrams. Later, CASE tools incorporated a type of intelligence that assisted in validating designs and ensuring conformity of diagrams. By the late 1980’s, CASE tools were being used to automatically generate code, based on design diagrams. In the early 1990’s, CASE tools had evolved into user-friendly interfaces that could be used on multiple projects, but still contained the aspects that had made previous CASE tools useful.
( B. Agarwal, Computer-Aided Software Engineering, p.77 )
(E. Biehl, Data-Oriented Quality Solutions, 2005, p. 6.)
5. Design for Six Sigma (Quality)
Previous Definition (Better)
The Six Sigma movement pushed these concepts to the extreme of targeting 6σ quality levels in the short-term that would achieve 4.5σ quality levels in the long-term. Defect rates at this quality level fall at about 3.4 defects per million opportunities. The variability of a 6σ process relative to its specification limits is illustrated in.
The quality movement toward Six Sigma effectively decoupled the definition of defects from defectives. At Six Sigma, defectives are still any observation outside of the customer’s specification limits, although such observations become exceedingly rare. Defects remain however, as roughly 3-7% of all observations will continue to fall outside of the control limits. With the control limits at 3σ, and the specification limits at 6σ, the vast majority of defects do not rise to a level close to resulting in a customer defective. Each defect, though, remains an opportunity to continue to improve the process and bring the expected process shift under control. By managing these defects effectively, the process continuously improves without ever producing a defective for the customer. That distinction – the 3σ to 6σ gap – is the essence and opportunity of Six Sigma Math.
(E. Biehl, Data-Oriented Quality Solutions, 2005, p. 6.)
New Definition
Design for six sigma (DFSS) is a proven, robust approach to designing new products and services and redesigning the flaws out of existing offerings. More ambitiously, DFSS can be applied to building new competitive capabilities that go beyond current customer expectations. DFSS is about leaping past incremental improvement. Its objective is creating products and processes that are practically immune to problems, that wow customers, and leave employees feeling positive and confident that they can deliver value and excellence. DFSS does not try to influence one or two key product features or process steps; it aims to influence practically everything about the product and the way it’s produced.
( R. Cavanagh, P. Neuman, S. Pande, What is Design for Six Sigma?, p.13)
No comments:
Post a Comment