Critical paths report | Construpedia

Critical paths report

Introduction

operations research, also called operational research or administrative science, is the field of study that studies the resolution of organizational control problems to achieve certain objectives.

through the application of advanced analytical methods to help make better decisions.[1] [2] It is part of Operations Management in the administrative discipline and industrial engineering.[3].

The origin of modern IoT lies in World War II and on the Allied side. In fact, some of the discoveries of those years (Wald's sequential quality control) remained a military secret until several years after the war ended. Armies are complex organizations with complex problems of coordination and logistics, weapons production and distribution, administration, advance strategies and troop deployment. The Allied command brought together scientists from various areas (mathematicians, physicists, engineers, statisticians, economists, among others) to address these complex problems. The name IO comes from that war objective: to investigate (military) operations.[4].

It is often considered to be a subfield of applied mathematics.[5] The terms management science and decision theory are sometimes used synonymously.[6].

Using techniques from other mathematical sciences, such as mathematical modeling, statistical analysis, and "Optimization (mathematical)") optimization, operations research arrives at optimal or near-optimal solutions to complex decision-making problems. Because of its emphasis on human-technology interaction and because of its focus on practical applications, operations research overlaps with other disciplines, particularly industrial engineering and production management, and is based on psychology and organizational science. Operations research is often concerned with determining the extreme values of some real-world objective: the maximums (of profit, return, or profitability) or minimums (of loss, risk, or cost). Originating in military efforts prior to World War II, its techniques have grown to address problems in different industries.[7].

Overview

Operations Research (OR) encompasses a wide range of problem-solving techniques and methods applied to improve decision-making and efficiency, such as simulation, optimization (Mathematical) Optimization, queuing theory and other stochastic process models, Markov decision process, econometric methods,

Critical paths report

Introduction

through the application of advanced analytical methods to help make better decisions.[1] [2] It is part of Operations Management in the administrative discipline and industrial engineering.[3].

It is often considered to be a subfield of applied mathematics.[5] The terms management science and decision theory are sometimes used synonymously.[6].

Overview

History

Contenido

En las décadas posteriores a las dos guerras mundiales, las herramientas de la investigación de operaciones se aplicaron más ampliamente a los problemas en los negocios, la industria y la sociedad. Desde entonces, la investigación operativa se ha expandido a un campo ampliamente utilizado en industrias que van desde productos petroquímicos a líneas aéreas, finanzas, logística y gobierno, enfocándose en el desarrollo de modelos matemáticos que pueden usarse para analizar y optimizar sistemas complejos, y se ha convertido en un área de investigación académica e industrial activa.[7].

Historical origins

In the 19th century, mathematicians such as Christiaan Huygens and Blaise Pascal (addressing the interrupted game problem) attempted to solve questions related to complex decisions by using probability calculus. Other mathematicians of the 18th and 19th centuries solved these types of problems using combinatorics. Charles Babbage's research into the cost of transportation and mail sorting led to England's universal "Penny Post" in 1840, and studies into the dynamic behavior of railway vehicles in defense of the gauge of the GWR.[10] Beginning in the 19th century, the study of inventory management could be considered the origin of modern operations research with the concept of economic order quantity developed by Ford W. Harris in 1913. Operations research may have originated in the efforts of military planners during World War I (convoy theory and Lanchester's Laws). Percy Williams Bridgman brought operations research to the problems of physics in the 1920s and would later try to extend them to the social sciences.[11].

Modern operational research originated at the Bawdsey Research Establishment in the United Kingdom in 1937 and was the result of an initiative by the establishment's superintendent, A. P. Rowe, who conceived the idea as a means of analyzing and improving the operation of the United Kingdom's proposed radar early warning system and its network of facilities (Chain Home) (CH). Initially, it analyzed the operation of radar equipment and its communication networks, later expanding to include the behavior of operational personnel. This revealed unappreciated limitations of the CH network and allowed corrective action to be taken.[12].

Scientists in the United Kingdom, including Patrick Blackett, Cecil Gordon, Solly Zuckerman, C. H. Waddington, Owen Wansbrough-Jones), Frank Yates, Jacob Bronowski and Freeman Dyson, and in the United States with George Dantzig looked for ways to make better decisions in areas such as logistics and training schedules.

Second World War

The modern field of operations research emerged during World War II. In this period, operations research was defined as "a scientific method of providing executive departments with a quantitative basis for making decisions about operations under their control."[13] The activity was also known as operational analysis (UK Ministry of Defense since 1962)[14] and quantitative management.[15]

During the Second World War, around 1,000 men and women participated in operational research in Britain, and around 200 scientists worked in this field for the British Army.[16].

Patrick Maynard Stuart Blackett worked for several different organizations during the war. Early in the conflict, while working for the Royal Aircraft Establishment (RAE), he created a team known as the "Circus", which helped reduce the number of air defense rounds required to shoot down an enemy aircraft from an average of over 20,000 at the start of the Battle of Britain to 4,000 in 1941.[17]

In 1941, Blackett moved from the RAE to the Navy, having worked first with the RAF Coastal Command in 1941 and then in early 1942 with the British Admiralty. Blackett's team at the Coastal Command Operational Research Section (CC-ORS) included two future Nobel Prize winners and many others who went on to become leading figures in their fields. They led to carried out a series of crucial analyzes that contributed to the war effort. Britain introduced the convoy system to reduce cargo ship losses, but while the principle of using warships to accompany merchant ships was accepted, it was not clear whether it was better for convoys to be small or large. Convoys travel at the speed of the slowest member, so small convoys can travel faster. It was also argued that German U-Boats would be more difficult for small convoys to detect. On the other hand, large convoys could deploy more warships against an attacker. Blackett's staff showed that losses suffered by convoys depended largely on the number of escort vessels present, rather than the size of the convoy. Their conclusion was that some large convoys are more defensible than many small ones.[20].

When conducting an analysis of the methods used by the RAF Coastal Command to hunt and destroy submarines, one of the analysts asked what color the planes were. As most of them were from Bomber Command, they were painted black for night operations. At the suggestion of CC-ORS, a test was conducted to see if that was the best color to camouflage the aircraft for daytime operations in the gray skies of the North Atlantic. Tests showed that, on average, white-painted planes were not seen until they were 20% closer than black-painted ones. This change indicated that 30% more submarines would be attacked and sunk with the same number of sightings.[21] As a result of these findings, Coastal Command changed its aircraft to use white undersides.

Other work conducted by the CC-ORS indicated that, on average, if the firing depth of depth charges were changed from 100 feet to 25 feet, effectiveness rates would go up. The reason was that if a U-boat saw an aircraft shortly before it reached the target, the charges would do no harm by exploding at 100 feet (because the U-boat would not have had time to descend to that depth) and if it saw the aircraft from very far from the target, it had time to alter its course underwater, so the chances of it being within the 20-foot impact zone of the charges were small. It was more efficient to attack submarines near the surface when the locations of targets were better known than to attempt to destroy them at greater depths when their positions could only be guessed. Before the configuration change from 100 feet to 25 feet, 1% of submerged submarines were sunk and 14% were damaged. After the change, 7% were sunk and 11% damaged (if you count submarines captured on the surface, even if they were attacked shortly after submerging, the numbers increased to 11% sunk and 15% damaged). Blackett observed that "there can be few cases in which so large an operational gain has been made by so small and simple a change of tactics".[22]

The Bomber Command Operational Research Section (BC-ORS) analyzed a report from a survey carried out by RAF Bomber Command. For the survey, they inspected all bombers returning from missions over Germany during a particular period. All damage caused by the German air defense was noted and it was recommended that armor be added to the most damaged areas. This recommendation was not adopted due to the fact that the aircraft returned with these damaged areas. It indicated that these areas were not vital, and adding armor to non-vital areas where damage is acceptable negatively affects aircraft performance. Their suggestion to remove some crew members so that the loss of an aircraft would result in lower personnel losses was also rejected. Blackett's team made the logical recommendation to place armor in areas that were completely intact from the damage on returning bombers. They reasoned that the data collection was biased, as it only included aircraft that returned to Gran. Brittany. The intact areas of the returned aircraft were probably the vital points that, if damaged, would result in the loss of the aircraft.[23]

[24] A similar story is cited about a similar damage assessment study completed in the United States by the Statistical Research Group at Columbia University.[25] and was the result of work done by Abraham Wald.[26].

When Germany organized its air defenses on the Kammhuber Line, the British realized that if RAF bombers flew in a tight linear formation they could overwhelm German night fighters flying singly, directed to their targets by ground controllers. It was then a matter of statistically calculating the losses caused by collisions between the bombers versus the losses caused by the night fighters to determine the separation at which the bombers should fly to minimize RAF losses.[27]

The ratio of the rate of change of output to input was a characteristic feature of operations research. By comparing the number of flight hours of Allied aircraft with the number of submarine sightings in a given area, it was possible to redeploy aircraft to more productive patrol areas. The comparison of these rates made it possible to establish "effectiveness ratios" useful in planning. The ratio of 60 sea mines laid per ship sunk was common to several campaigns: German mines in British ports, British mines on German routes, and United States mines on Japanese routes.[28]

Operational research doubled the bombing hit rate of the Boeing B-29 Superfortresses attacking Japan from the Mariana Islands by increasing the proportion of training from 4 to 10 percent of flight hours; revealed that the wolf packs of three US submarines were the most effective number; showed that gloss enamel paint was a more effective camouflage for night fighters than the traditional dull camouflage paint finish, and that the smooth finish of the paint increased the speed of aircraft by reducing the friction of the fuselages with the air.[28].

On the ground, operational research sections of the Army Operational Research Group (AORG) of the Ministry of Supply (MoS) were deployed to the Battle of Normandy in 1944, and followed British forces as they advanced into central Europe. They analyzed, among other topics, the effectiveness of artillery, aerial bombardment and anti-tank fire.

After World War II

With expanded techniques and growing awareness on the ground at the end of the war, operational research was no longer limited to tactics alone, but expanded to encompass equipment acquisition, training, logistics, and infrastructure. Operations research also grew in many other areas besides the military once scientists learned to apply its principles to the civilian sector. With the development of the simplex algorithm for linear programming in 1947[29] and the development of computers in the following three decades".[29].

Issues addressed

• - Critical path method or project planning: identification of the processes that affect the overall duration of a complex project.

• - Floorplanning"): design of factory equipment or components of an integrated circuit to reduce manufacturing time (therefore, reduce cost).

• - Network optimization: for example, configuring telecommunications networks or the power system to maintain service quality during service interruptions.

• - Allocation problems.

• - Facility location&action=edit&redlink=1 "Facility location (optimization problem) (not yet written)".

• - Assignment problems:

Assignment problem

*Generalized allocation problem")

Quadratic assignment problem

Target assignment problem").

• - Bayesian search theory"): goal search.

• - Optimized search").

• - Routing, such as determining bus routes so that the fewest buses possible are needed.

• - Supply chain management: managing the flow of raw materials and products based on uncertain demand for finished products.

• - Project production activities: managing the flow of work activities in a capital project in response to system variability through operations research tools for variability reduction and buffer allocation using a combination of capacity, inventory and time allocation[30][31].

• - Efficient messages and customer response tactics.

• - Industrial automation: automation or integration of robotic systems into human-driven operations processes.

• - Globalization: processes of globalization of operations to take advantage of cheaper materials, labor, land or other productivity inputs.

• - Transportation: management of transportation and delivery systems (freight ("Examples: LTL shipping"), intermodal transportation, traveling salesman problem).

• - Planning:

Personnel organization")

Manufacturing steps

Project management

Network data traffic: these are known as queuing theory or queuing systems

Sports events and their television coverage.

• - Mixture of raw materials in oil refineries.

• - Determination of optimal prices, in many retail and B2B settings, within the disciplines of pricing science").

• - Value cutting problem: cutting small items from larger sizes.

Operations research is also widely used in government, where evidence-based policy is used.

Management science

En 1967, Stafford Beer caracterizó el campo de la ciencia de la administración como "el uso comercial de la investigación de operaciones".[32] Sin embargo, en los tiempos modernos el término ciencia de la administración también se puede usar para referirse a los campos separados de los estudios organizacionales o estrategia de negocios. La ciencia de la gestión es una rama interdisciplinaria de las matemáticas aplicadas dedicada a la planificación óptima de decisiones, con fuertes vínculos con la economía, los negocios, la ingeniería y otras ciencias. Utiliza varios principios basados en investigación científica, estrategias "Estrategia (juegos)") y técnicas analíticas, incluyendo modelado matemático, estadísticas y análisis numérico con el fin de mejorar la capacidad de una organización para adoptar decisiones de gestión racionales y significativas al llegar a soluciones óptimas o casi óptimas para problemas complejos de decisión. Los científicos de gestión ayudan a las empresas a lograr sus objetivos utilizando los métodos científicos de la investigación operativa.

El mandato del científico de la administración es utilizar técnicas racionales, sistemáticas y basadas en la ciencia para informar y mejorar las decisiones de todo tipo. Por supuesto, las técnicas de la ciencia de la administración no se limitan a aplicaciones comerciales, sino que pueden aplicarse a militares, médicos, administración pública, grupos caritativos, grupos políticos o a comunidades.

La ciencia de la administración tiene que ver con el desarrollo y la aplicación de modelos") y conceptos que pueden resultar útiles para ayudar a iluminar los problemas de la administración y resolver problemas de gestión, así como para diseñar y desarrollar nuevos y mejores modelos de excelencia organizacional.[33].

La aplicación de estos modelos dentro del sector corporativo se conoció como ciencia de la gestión.[34].

Some of the fields that have considerable overlap with Operations Research and Management Science include:[35].

Applications

Applications are abundant, such as in airlines, manufacturing companies, service club, military branches and government. The range of problems and problems to which he has contributed ideas and solutions is very wide. Includes:[33].

• - Scheduling (of airlines, trains, buses, etc.).

• - Assignment (assignment of personnel to flights, trains or buses; employees to projects; commitment and dispatch of power generation facilities).

• - Facility location (decide the most suitable location for new facilities, such as warehouse, factory or fire station).

• - Hydraulic and pipeline engineering (reservoir water flow management).

• - Health services (information and supply chain management).

• - Game theory (identification, understanding, development of strategies adopted by companies).

• - Urban design.

• - Computer network engineering (packet routing; timing; analysis).

• - Telecommunications and data communication engineering (packet routing; timing; analysis)[36].

Management is also concerned with so-called 'soft operational analysis' which refers to methods for strategic planning, decision support systems, and problem structuring methods.

When dealing with these types of challenges, mathematical modeling and simulation may not be appropriate or may not be sufficient. Therefore, several non-quantized modeling methods have been developed since the 1990s. These include:

• - Stakeholder-based approaches, including metagame analysis and drama theory.

• - Morphological analysis&action=edit&redlink=1 "Morphological analysis (problem solving) (not yet written)" and various forms of influence diagrams").

• - Cognitive correspondence.

• - Strategic choice.

• - Robustness analysis.

Societies and magazines

Companies

The International Federation of Operational Research Societies") (IFORS)[37] is an umbrella organization for operations research societies worldwide, representing approximately 50 national societies, including those in the United States,[38] United Kingdom (Operational Research Society"),[39] France,[40] Germany, Italy (Italian Operations Research Society"),[41] Canada,[42] Australia,[43] New Zealand,[44] Philippines,[45] India,[46] Japan and South Africa[47] IFORS constituent members form regional groups, such as the European Association of European Operational Research Societies (EURO).[48] Other important operations research organizations are the Simulation Interoperability Standards Organization (SISO)[49] and the Interservice/Industry Training, Simulation and Education Conference") (I/ITSEC).[50].

In 2004, the United States-based INFORMS organization began an initiative to better market the activity of operations research professionals, including a website titled "The Science of Better"[51] that provides an introduction to operations research and examples of its successful application to industrial problems. This initiative has been adopted by the Operational Research Society in the United Kingdom, including a website titled "Learn about OR".[52].

INFORMS Magazines

The Institute for Operations Research and the Management Sciences (INFORMS) publishes thirteen academic journals on operations research, including the two largest journals of their kind, according to the Journal Citation Reports.[53] 2005:.

• - Decision analysis[54].

• - Information systems research[55].

• - INFORMS Journal on Computing[56].

• - INFORMS Transactions on Education[57] (an open access journal).

• - Interfaces[58].

• - Management Science&action=edit&redlink=1 "Management Science (journal) (not yet written)").

• - Manufacturing & Service Operations Management").

• - Marketing Science&action=edit&redlink=1 "Marketing Science (journal) (not yet written)").

• - Mathematics of Operations Research").

• - Operations Research&action=edit&redlink=1 "Operations Research (magazine) (not yet written)").

• - Organization Science[59].

• - Service Science[60].

• - Transportation Science").

Other magazines

Listed according to the alphabetical order of their titles:.

• - 4OR")-A Quarterly Journal of Operations Research: joint publication of the Operations Research Societies of Belgium, France and Italy (Springer);.

• - Decision Sciences"): published by Wiley-Blackwell on behalf of the Decision Sciences Institute");.

• - European Journal of Operational Research (EJOR): Founded in 1975, it is by far the largest operations research journal in the world, with around 9,000 pages of articles published per year. In 2004, its total number of citations was the second largest among operational research and management science journals.

• - INFOR Journal: published and sponsored by the Canadian Operational Research Society;.

• - International Journal of Operations Research and Information Systems (IJORIS): an official publication of the Information Resources Management Association, published quarterly by IGI Global;[61].

• - Journal of Defense Modeling and Simulation (JDMS): Applications, Methodology, Technology: a quarterly publication dedicated to the advancement of the science of modeling and simulation as it relates to the military and defense;[62].

• - *Journal of the Operational Research Society"): official journal of The OR Society"); is the world's oldest still-active journal on IoT, published by Taylor and Francis;.

• - Military Operations Research (MOR): published by Military Operations Research Society");.

• - Omega - The International Journal of Management Science;.

• - Operations Research Letters;.

• - Opsearch: official magazine of the Operational Research Society of India;.

• - OR Insight: a quarterly magazine of The OR Society, published by Palgrave;[63].

• - Production and Operations Management"): official journal of the Production and Operations Management Society.

• - TOP: official journal of the Spanish IoT Society").[64].

Additional reading

Classic books and articles

• - R. E. Bellman, Dynamic Programming, Princeton University Press, Princeton, 1957.

• - Abraham Charnes, William W. Cooper, Management Models and Industrial Applications of Linear Programming, Volumes I and II, New York, John Wiley & Sons, 1961.

• - Abraham Charnes, William W. Cooper, A. Henderson, An Introduction to Linear Programming, New York, John Wiley & Sons, 1953.

• - C. West Churchman, Russell L. Ackoff & E. L. Arnoff, Introduction to Operations Research, New York: J. Wiley and Sons, 1957.

• - George B. Dantzig, Linear Programming and Extensions, Princeton, Princeton University Press, 1963.

• - Lester K. Ford, Jr., D. Ray Fulkerson, Flows in Networks, Princeton, Princeton University Press, 1962.

• - Jay W. Forrester, Industrial Dynamics, Cambridge, MIT Press, 1961.

• - L. V. Kantorovich, “Mathematical Methods of Organizing and Planning Production” Management Science, 4, 1960, 266–422.

• - Ralph Keeney, Howard Raiffa, Decisions with Multiple Objectives: Preferences and Value Tradeoffs, New York, John Wiley & Sons, 1976.

• - H. W. Kuhn, "The Hungarian Method for the Assignment Problem," Naval Research Logistics Quarterly, 1–2, 1955, 83–97.

• - H. W. Kuhn, A. W. Tucker, "Nonlinear Programming," pp. 481–492 in Proceedings of the Second Berkeley Symposium on Mathematical Statistics and Probability.

• - B. O. Koopman, Search and Screening: General Principles and Historical Applications, New York, Pergamon Press, 1980.

• - Tjalling C. Koopmans, editor, Activity Analysis of Production and Allocation, New York, John Wiley & Sons, 1951.

• - Charles C. Holt, Franco Modigliani, John F. Muth, Herbert A. Simon, Planning Production, Inventories, and Work Force, Englewood Cliffs, NJ, Prentice-Hall, 1960.

• - Philip M. Morse, George E. Kimball, Methods of Operations Research, New York, MIT Press and John Wiley & Sons, 1951.

• - Robert O. Schlaifer, Howard Raiffa, Applied Statistical Decision Theory, Cambridge, Division of Research, Harvard Business School, 1961.

Classic textbooks

• - Frederick S. Hillier & Gerald J. Lieberman, Introduction to Operations Research, McGraw-Hill: Boston MA; 10th Edition, 2014.

• - Taha, Hamdy A., "Operations Research: An Introduction", Pearson, 10th Edition, 2016.

• - Robert J. Thierauf & Richard A. Grosse, "Decision Making Through Operations Research", John Wiley & Sons, INC, 1970.

• - Harvey M. Wagner, Principles of Operations Research, Englewood Cliffs, Prentice-Hall, 1969.

History

• - Saul I. Gass, Arjang A. Assad, An Annotated Timeline of Operations Research: An Informal History. New York, Kluwer Academic Publishers, 2005.

• - Saul I. Gass (Editor), Arjang A. Assad (Editor), Profiles in Operations Research: Pioneers and Innovators. Springer, 2011.

• - Maurice W. Kirby (Operational Research Society (Great Britain)). Operational Research in War and Peace: The British Experience from the 1930s to 1970, Imperial College Press, 2003. ISBN 1-86094-366-7, ISBN 978-1-86094-366-9.

• - J. K. Lenstra, A. H. G. Rinnooy Kan, A. Schrijver (editors) History of Mathematical Programming: A Collection of Personal Reminiscences, North-Holland, 1991.

• - Charles W. McArthur, Operations Analysis in the U.S. Army Eighth Air Force in World War II, History of Mathematics, Vol. 4, Providence, American Mathematical Society, 1990.

• - C. H. Waddington, O. R. in World War 2: Operational Research Against the U-boat, London, Elek Science, 1973.

• - Wikiquote hosts famous quotes from or about Operations Research.

• - What is operations research?

• - International Federation of Operations Research Societies.

• - The Institute of Operations Research and Management Sciences (INFORMATIVES).

• - Occupational Outlook Manual, US Department of Labor, Bureau of Labor Statistics.

History

Contenido

Historical origins

Second World War

During the Second World War, around 1,000 men and women participated in operational research in Britain, and around 200 scientists worked in this field for the British Army.[16].

After World War II

Issues addressed

• - Critical path method or project planning: identification of the processes that affect the overall duration of a complex project.

• - Floorplanning"): design of factory equipment or components of an integrated circuit to reduce manufacturing time (therefore, reduce cost).

• - Network optimization: for example, configuring telecommunications networks or the power system to maintain service quality during service interruptions.

• - Allocation problems.

• - Facility location&action=edit&redlink=1 "Facility location (optimization problem) (not yet written)".

• - Assignment problems:

Assignment problem

*Generalized allocation problem")

Quadratic assignment problem

Target assignment problem").

• - Bayesian search theory"): goal search.

• - Optimized search").

• - Routing, such as determining bus routes so that the fewest buses possible are needed.

• - Supply chain management: managing the flow of raw materials and products based on uncertain demand for finished products.

• - Efficient messages and customer response tactics.

• - Industrial automation: automation or integration of robotic systems into human-driven operations processes.

• - Globalization: processes of globalization of operations to take advantage of cheaper materials, labor, land or other productivity inputs.

• - Transportation: management of transportation and delivery systems (freight ("Examples: LTL shipping"), intermodal transportation, traveling salesman problem).

• - Planning:

Personnel organization")

Manufacturing steps

Project management

Network data traffic: these are known as queuing theory or queuing systems

Sports events and their television coverage.