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Johnson's Rule
In operations research, Johnson's rule is a method of scheduling jobs in two work centers. Its primary objective is to find an optimal sequence of jobs to reduce makespan (the total amount of time it takes to complete all jobs). It also reduces the amount of idle time between the two work centers. The method minimizes the makespan in the case of two work centers. Furthermore, the method finds the shortest makespan in the case of three work centers if additional constraints are met. Algorithm The technique requires several preconditions: * The time for each job must be invariant with respect to when it is done. * Job times must be independent of the job sequence. * All jobs must be processed in the first work center before going through the second work center. * All jobs are equally prioritised. Johnson's rule is as follows: # List the jobs and their times at each work center. # Select the job with the shortest activity time. If that activity time is for the first work center, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Operations Research
Operations research () (U.S. Air Force Specialty Code: Operations Analysis), often shortened to the initialism OR, is a branch of applied mathematics that deals with the development and application of analytical methods to improve management and decision-making. Although the term management science is sometimes used similarly, the two fields differ in their scope and emphasis. Employing techniques from other mathematical sciences, such as mathematical model, modeling, statistics, and mathematical optimization, optimization, operations research arrives at optimal or near-optimal solutions to decision-making problems. Because of its emphasis on practical applications, operations research has overlapped with many other disciplines, notably industrial engineering. Operations research is often concerned with determining the extreme values of some real-world objective: the Maxima and minima, maximum (of profit, performance, or yield) or minimum (of loss, risk, or cost). Originating in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Primary Objective
A goal or objective is an idea of the future or desired result that a person or a group of people envision, plan, and commit to achieve. People endeavour to reach goals within a finite time by setting deadlines. A goal is roughly similar to a purpose or aim, the anticipated result which guides reaction, or an end, which is an object, either a physical object or an abstract object, that has intrinsic value. Goal setting Goal-setting theory was formulated based on empirical research and has been called one of the most important theories in organizational psychology. Edwin A. Locke and Gary P. Latham, the fathers of goal-setting theory, provided a comprehensive review of the core findings of the theory in 2002. In summary, Locke and Latham found that specific, difficult goals lead to higher performance than either easy goals or instructions to "do your best", as long as feedback about progress is provided, the person is committed to the goal, and the person has the ability a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sequence
In mathematics, a sequence is an enumerated collection of objects in which repetitions are allowed and order matters. Like a set, it contains members (also called ''elements'', or ''terms''). The number of elements (possibly infinite) is called the ''length'' of the sequence. Unlike a set, the same elements can appear multiple times at different positions in a sequence, and unlike a set, the order does matter. Formally, a sequence can be defined as a function from natural numbers (the positions of elements in the sequence) to the elements at each position. The notion of a sequence can be generalized to an indexed family, defined as a function from an ''arbitrary'' index set. For example, (M, A, R, Y) is a sequence of letters with the letter "M" first and "Y" last. This sequence differs from (A, R, M, Y). Also, the sequence (1, 1, 2, 3, 5, 8), which contains the number 1 at two different positions, is a valid sequence. Sequences can be '' finite'', as in these examples, or '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Makespan
In operations research Operations research () (U.S. Air Force Specialty Code: Operations Analysis), often shortened to the initialism OR, is a branch of applied mathematics that deals with the development and application of analytical methods to improve management and ..., the makespan of a project is the length of time that elapses from the start of work to the end. This type of multi-mode resource constrained project scheduling problem (MRCPSP) seeks to create the shortest logical project schedule, by efficiently using project resources, adding the lowest number of additional resources as possible to achieve the minimum makespan. The term commonly appears in the context of scheduling. Example There is a complex project that is composed of several sub-tasks. We would like to assign tasks to workers, such that the project finishes in the shortest possible time. As an example, suppose the "project" is to feed the goats. There are three goats to feed, one child can only feed on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Idleness
Idleness is a lack of motion or energy. In describing a person, ''idle'' suggests having no labor: "idly passing the day". In physics, an idle machine exerts no transfer of energy. When a vehicle is not in motion, an idling engine does no useful thermodynamic work. In computing, an idle processor or network circuit is not being used by any program, application, or message. Cultural norms Typically, when one describes a machine as idle, it is an objective statement regarding its current state. However, when used to describe a person, idle typically carries a negative connotation, with the assumption that the person is wasting their time by doing nothing of value. Such a view is reflected in the proverb "an idle mind is the devil's workshop". Also, the popular phrase " killing time" refers to idleness and can be defined as spending time doing nothing in particular in order that time seems to pass more quickly. These interpretations of idleness are not universal – they ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Skill
A skill is the learned or innate ability to act with determined results with good execution often within a given amount of time, energy, or both. Skills can often be divided into domain-general and domain-specific skills. Some examples of general skills include time management, teamwork and leadership, and self-motivation. In contrast, domain-specific skills would be used only for a certain job, e.g. operating a sand blaster. Skill usually requires certain environmental stimuli and situations to assess the level of skill being shown and used. A skill may be called an art when it represents a body of knowledge or branch of learning, as in ''the art of medicine'' or ''the art of war''. Although the arts are also skills, there are many skills that form an art but have no connection to the fine arts. People need a broad range of skills to contribute to the modern economy. A joint ASTD and U.S. Department of Labor study showed that through technology, the workplace is chang ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Preconditions
In computer programming, a precondition is a condition or predicate that must always be true just prior to the execution of some section of code or before an operation in a formal specification. If a precondition is violated, the effect of the section of code becomes undefined and thus may or may not carry out its intended work. Preconditions that are missing, insufficient, or not formally proved (or have an incorrect attempted proof), or are not checked statically or dynamically, can give rise to Security problems, particularly in unsafe languages that are not strongly typed. Often, preconditions are simply included in the documentation of the affected section of code. Preconditions are sometimes tested using guards or assertions within the code itself, and some languages have specific syntactic constructions for doing so. Example The factorial function is only defined where its parameter is an integer greater than or equal to zero. So an implementation of the factorial fu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arbitrariness
Arbitrariness is the quality of being "determined by chance, whim, or impulse, and not by necessity, reason, or principle". It is also used to refer to a choice made without any specific criterion or restraint. Arbitrary decisions are not necessarily the same as random decisions. For example, during the 1973 oil crisis, Americans were allowed to purchase gasoline only on odd-numbered days if their license plate was odd, and on even-numbered days if their license plate was even. The system was well-defined and not random in its restrictions; however, since license plate numbers are completely unrelated to a person's fitness to purchase gasoline, it was still an arbitrary division of people. Similarly, schoolchildren are often organized by their surname in alphabetical order, a non-random yet an arbitrary method—at least in cases where surnames are irrelevant. Philosophy Arbitrary actions are closely related to teleology, the study of purpose. Actions lacking a ''telos (philosop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Production Planning
Production planning is the planning of Production (economics), production and manufacturing modules in a company or industry. It utilizes the resource allocation of activities of employees, raw material, materials and production capacity, in order to serve different customers.Fargher, Hugh E., and Richard A. Smith. "Method and system for production planning." U.S. Patent No. 5,586,021. 17 Dec. 1996. Different types of production methods, such as single item manufacturing, batch production, mass production, continuous production etc. have their own type of production planning. Production planning can be combined with production control into production planning and control, or it can be combined with enterprise resource planning. Overview Production planning is the future of production. It can help in efficient manufacturing or setting up of a production site by facilitating required needs. A production plan is made periodically for a specific time period, called the planning ho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
