Hochregale Hochregale sind wirtschaftlich und effizient
12.10.2007 | Autor: Gerd Knehr
Dass heute Erweiterung, Umbau und Optimierung der Materialflusskomponenten einen sicheren und ungestörten Betrieb ermöglichen müssen, das beweisen insbesondere auch die Hersteller komplexer Hochregallager.
Die Silobauweise gibt bei Regalhöhen bis 30 m in Bezug auf Verformung unter Wind oder Einhaltung der Toleranzen kaumProbleme auf. Bild: Kocher Die Silobauweise gibt bei Regalhöhen bis 30 m in Bezug auf Verformung unter Wind oder Einhaltung der Toleranzen kaumProbleme auf. Bild: Kocher Produkte werden in immer geringeren Losgrößen und in immer höheren Frequenzen verschickt. Dies hebt die Logistikkosten pro Stück. Vor dem Hintergrund dieser Strukturverschiebung besteht ein großes Innovationspotenzial in der Entwicklung effizienter Lagertechnik und Logistiklösungen zur Reduktion der Kosten entlang der Supply Chain.
Anforderungen an Hochregale sind nicht branchenspezifisch
Manfred W. Schleicher, Leiter des Vertrieb und Marketings automatisierter Systeme bei SSI Schäfer Noell, bekundet: „Wir sehen zwei Trendrichtungen: zum einen zu mehr Automatisierung, zum anderen zu mehr Flexibilität. Der Grad von Automatisierung und Flexibilität ist kundenindividuell zu betrachten. Vor allem in der Distribution im Handel ist verstärkt ein Trend in Richtung Kombination von automatischem Kleinteilelager (AKL) und Hochregallager (HRL) erkennbar. In vielen Fällen wird das Palettenlager nur noch für Großmengen oder als Nachschublager verwendet. Mit dem AKL und unserem SCS oder SQS stellen wir den Durchsatz für die Hochleistungskommissionierung her. In solchen Systemen sind Durchsatzleistungen von 200 Doppelspielen in der Stunde (DS/h) und mehr absolut üblich. Nur durch solche Kombinationen ist es möglich, den Anforderungen an Leistung und Service im Handel gerecht zu werden.“
Für den wirtschaftlichen Betrieb eines Distributionszentrums ist es in erster Linie entscheidend, wie effizient durchzuführende Aufgaben abgewickelt werden. Dazu reicht es nicht aus, dass eine Anlage im Distributionszentrum effizient integriert ist, sondern sie muss dafür auch geeignet sein. Ein Durchlaufregallager beispielsweise kann die Effizienz solch einer Anlage verbessern.
Für den Einsatz von Hochregallagern gibt es unterschiedliche Gründe wie:
*
Flächeneinsparung durch optimierte Lagerung *
Automatisierung von Prozessketten *
Erhöhung der Qualität und Bestandssicherheit *
Verbesserung der Ergonomie und Kommissioniereffizienz.
Alfred Kocher, der Geschäftsführer von Kocher Regalbau, unterstreicht: „Die Anforderungen an Hochregalanlagen sind nicht branchenspezifisch. Ob Automobilindustrie, Getränkehandel oder Textilherstellung, eine Lagerlösung orientiert sich in der Regel immer an der gestellten Aufgabe und den möglichen baulichen Maßen. So sind auch die Anforderungen je nach Kunde und Bedarfsfall unterschiedlich. Bei Regalhöhen bis zu 30 m gibt es in Bezug auf die Verformung unter Wind sowie die Einhaltung der Toleranzen kaum Probleme. Was darüber hinaus geht, kann nicht mehr nach den baulichen Normen alleine betrachtet werden. Die noch zulässigen Verformungen und Toleranzen sind hier zu berücksichtigen. Dies betrifft die statische und die konstruktive Auslegung ebenso wie die erforderliche Montagetechnik. Wir bauen derzeit zum Beispiel zwei Anlagen mit etwa 50 m Höhe, die sicherlich einen Höhenrekord darstellen, was insgesamt bautechnisch enorme Anforderungen an alle entsprechenden Kriterien stellt. Gelöst wurden alle notwendigen Vorgaben durch die intensive Zusammenarbeit der Lieferanten der einzelnen Komponenten.“
Als Generalunternehmer und Systemintegrator hat SSI Schäfer bereits Palettenlager mit einer Regalhöhe bis 45 m und einer Regallänge von annähernd 200 m sowie einer Kapazität von über 150 000 Stellplätzen realisiert. „Bezüglich der Kapazitäten sind eigentlich keine Grenzen gesetzt. Grundsätzlich ist jedoch ein sinnvolles Längen-Höhen-Verhältnis des Hochregallagers anzustreben, um Wirtschaftlichkeit zu erzielen“, betont Manfred Schleicher. Und Alfred Kocher fügt an: „Bei der sinnvollen Auslegung eines Lagersystems sollte das Zusammenspiel zwischen Schnelldrehern, Langsamdrehern und allgemeiner Verfügbarkeit über ein geeignetes Steuerungsprogramm gelöst werden. So werden zum Beispiel die Schnelldreher nahe der Vorzone und die Langsamdreher in der Hinterzone gelagert.“ Logistikgebäude werden immer häufiger zur Drittverwertung der Immobilien typisiert
Exemplarische und repräsentative Lösungen für Materialfluss-Komponenten der „neuen Generation“, die ergonomisch integriert das Personal unterstützen, sind platzsparend statt raumfressend sowie energie- und ressourcensparend ausgelegt. Darüber hinaus beobachtet Manfred Schleicher eine zunehmende Typisierung von Logistikgebäuden, um eine Drittverwendung der Immobilien sicherzustellen. Es würden vermehrt Hallen gemietet oder geleast, so dass bei der Wahl der Regaltechnik darauf geachtet werde, dass der Ab- oder Umbau der Anlage problemlos und ohne Beschädigung der Gebäude vollzogen werden könne. Bildergalerie Klicken Sie auf ein Bild um die Bildergalerie zu öffnen Besonders im Handel ist ein Trend zu automatischen Kleinteilelagern und manuell bedienten oder einfahrbaren Hochregalen feststellbar. Bild: SSI Schäfer Kurvengängige Regalbediengeräte schaffen rund 25 bis 30 Ein- und Auslagerungen, sogenannte Doppelspiele, pro Stunde. Bild: Dambach
Viele Logistikdienstleister, die bei Vertragslaufzeiten von teilweise bis zu drei Jahren darauf angewiesen sind, bei verändertem Anforderungsprofil ihrer Kunden die eigene Lagertechnik schnell und kostengünstig umzurüsten, setzen daher auf flexible Regalsysteme. Auf diese Situation reagiert SSI Schäfer mit dem „Palettenregal zur Miete“. Durch kurze Vertragslaufzeiten und schnelle Verfügbarkeit des Regals wird die Flexibilität der Kunden unterstützt, so dass diese schnell auf ihre jeweiligen Lageranforderungen reagieren können.
Flexible Hochregalsysteme zur Miete gefragt
Dass die Technik schon allein unter wirtschaftlichen Gesichtspunkten kein Selbstzweck ist, scheint auf den ersten Blick selbstverständlich. Automatisierte Lager und mit Schmalgangstaplern betriebene Anlagen stellen verschiedene Lagerformen dar. Alfred Kocher bekräftigt: „Eine sinnvolle Kombination ist nicht erreichbar. Bei Anlagen mit einem hohen Umschlag sind ausschließlich Regalbediengeräte zu empfehlen. Schmalgangstapler sind für einen hohen Umschlag zu schwerfällig. Viele kinematische Rechenbeispiele haben dies bewiesen. Anlagen mit umsetzbaren Regalbediengeräten (RBG) sind schon vielfach gebaut worden. Diese Anlagen können im Gegensatz zu Anlagen mit Schmalgangstaplern ohne weiteres voll automatisiert werden. Obwohl der Umsetzvorgang ungefähr gleich viel Zeit wie das Umsetzen mit einem Schmalgangstapler benötigt, ist durch die Automatisierung ein RBG-betriebenes Lager zweckmäßiger.“
Jörg Marx, Leiter des Vertriebs und der Projektierung für Regalbediengeräte bei Dambach Lagersysteme, bekräftigt: „Im Leistungsvergleich schafft ein kurvengängiges RBG, das zwei Gassen bedient, etwa 25 bis 30 DS/h und ein ganggebundenes RBG annähernd 35 bis 70 DS/h; ein manuell bedienter Stapler hingegen höchstens 15 bis 20 DS/h.“ So hat hinsichtlich der Verfügbarkeitsanforderung das kurvengängige System an Bedeutung zugenommen, da im Störfall das benachbarte RBG die Aufgaben des ausgefallenen übernehmen kann. Im Bereich der Hochleistungsregalbediengeräte hat Dambach den Gerätetyp 18M entwickelt. Jörg Marx betont: „Unsere Regalbediengeräte der M-Klasse erreichen Leistungsbereiche, die sonst nur bei AKL üblich sind. Auf Wunsch bietet die M-Klasse sogar eine nachträgliche Leistungssteigerung – sozusagen aus dem Baukasten. Nachträgliche Leistungserhöhungen können zum Beispiel durch das Anbringen weiterer Antriebe realisiert werden. Das ermöglicht einen stufenweisen und anwendungsorientierten Ausbau der Geräte.“
Für Hochregaltechnik ist noch lange kein Ersatz in Sicht
Alfred Kocher bringt es auf den Punkt: „1968 haben wir den ersten automatisierten Hochregalsilo entwickelt und gebaut. Seitdem sind hauptsächlich in der Förder- und Steuerungstechnik enorme Fortschritte gemacht worden. In Bezug auf die Regalanlage selbst sind keine grundsätzlichen Änderungen erfolgt. Verbesserungen und Weiterentwicklungen einzelner Regalkomponenten haben sich jedoch in vielerlei Hinsicht ergeben. Vor einigen Jahren hat uns ein bekannter Planer auf den Warenumsatz im Just-in-time-Verfahren mit der Aussage konfrontiert, dass es in naher Zukunft keine Hochregallager mehr geben werde, da sie durch diese neue Technik überholt seien. Unsere Antwort war damals wie heute, dass überall, wo Ware hergestellt, zwischengelagert und versandt wird, ein Puffer notwendig ist, insbesondere, wenn ‚just in time‘ angeliefert werden muss. So ist es auch geblieben. Es ist nicht absehbar, ob die Hochregallagertechnik in Zukunft durch eine andere ersetzt werden kann. Wir glauben nicht, dass ein Ersatz möglich ist.“
Voraussetzung für den weiteren Siegeszug der Hochregallager-Technik sei jedoch die ständige Weiterentwicklung und Verbesserung der einzelnen Komponenten. Dies geschehe am Markt schon allein durch den Konkurrenzdruck, betont der Lagerexperte. Und Jörg Marx fügt hinzu: „In der Geräteklasse der Regalbediengeräte über 30 m Hubhöhe liegt die Herausforderung der Zukunft in der statischen Dimensionierung und der damit verbundenen Gewichtsreduzierung. Es ist manchmal schon etwas befremdend, wenn 35 t Stahl – so viel wiegt ein RGB – bewegt werden müssen, um eine Palette mit 1000 kg zu transportieren.“
Dipl.-Phys. Gerd Knehr ist freier Fachjournalist in 72760 Reutlingen, Tel./Fax. (0 71 21) 6 11 11, gerdknehr@aol.com
Which are the world's most diversified exporting nations?
EUROPEAN countries are highly diversified exporters. Italy is the most diversified in the world—its biggest five export products, which include cars and footwear, made up 12.9% of total exports in 2005 according to the World Bank's “World Trade Indicators 2008” published on Tuesday June 17th. Newer members of the EU benefit from cheaper labour costs and so export more factory-made goods. America also exports a wide range of products—its top exports include high-tech products such as microcircuits.
THE Japanese make most visits to the doctor of any rich country. Each person goes 13.8 times a year on average according to the OECD. The high rate could be explained in part by Japan's high ratio of older people who require more care. Americans see a doctor less than four times a year, although the high number people without medical insurance may be a factor. Neighbouring Mexicans are the most doctor-shy.
Microsoft's latest operating system makes it easier to integrate location detection with other services.
By Duncan Graham-Rowe
Internet-enabled services could become more common in vehicles, thanks to a new operating system launched this week by Microsoft. Dubbed Windows Embedded NavReady 09, the operating system is designed to improve wireless connectivity and Internet access in GPS devices. It also includes Bluetooth features that allow GPS receivers to be coupled with other devices, such as cell phones, PDAs, and laptops.
"The industry mostly knows us for Windows PC, Windows Mobile, Zune, and Xbox," says Dan Javnozon, senior product manager of Windows Embedded. But for the past 11 years, he says, Microsoft has been supplying embedded operating systems for everything from huge industrial robots and home automation appliances to temperature controls and some GPS devices.
Credit: Technology Review
Whereas the desktop version of Windows adds new functions and requires more memory with every release, embedded operating systems sacrifice versatility for leanness and efficiency. Currently, most GPS companies, such as TomTom and Garmin, use their own custom-built, proprietary operating systems. Others use off-the-shelf embedded systems that may not be ideal for GPS technology. Mio, for instance, uses an existing Microsoft operating system called Windows Embedded Compact, which is designed for real-time handheld devices.
Because GPS devices require relatively powerful operating systems, it can be expensive for companies to develop their own. NavReady makes it easy for GPS receivers to share data with other hardware, so it should reduce the complexity and cost of building and testing Internet-connected GPS devices. "I think Microsoft is laying the foundations for what we see as one of the big frontiers for navigation devices--connectivity," says Clint Wheelock, chief research officer with ABI Research, in New York City.
Like Microsoft's other embedded software platforms, NavReady is modular, says Javnozon: developers can discard the code they don't need, which should make their systems more efficient. "They can pick and choose components, like Lego blocks," Javnozon says.
Microsoft believes that the new operating system will help people retrieve more up-to-date information about nearby places, people, and services. The problem with current location-based services, says Wheelock, is that when they search for points of interest--such as restaurants, businesses, museums, and parks--they simply query a static database stored on the GPS device, which only rarely gets updated.
Existing traffic-notification services have a similar problem, Wheelock says. They generally send out information on a broadcast basis, he says, so drivers are not necessarily getting the latest real-time information, which can be crucial to, say, deciding which route to take home after work.
Javnozon says that by making it easier for developers to add Internet access to their GPS devices, NavReady will enable two-way communication and ensure that the very latest information is retrieved. "It allows you to search for points of interest directly on the Internet within a Windows Live database," he says.
"In Europe, about 20 percent of drivers already have some form of navigational device, while in the U.S., it's more like 10 percent," says Chris Jones, a principal analyst with Canalys, in Reading, England. The market for automotive GPS devices is expanding rapidly, Jones says, but NavReady will likely spur innovation and competition. For example, although some high-end products on the market already have Internet and Bluetooth functions, he says, NavReady should make these features fast become the norm.
Similarly, other applications are likely to emerge from the increased connectivity of GPS devices, such as location-based social networking, says Wheelock.
Although launched this week, NavReady is currently available only to device makers. So we shouldn't expect devices that use it to hit the market until 2009. And when they do, don't expect any kind of familiar Windows interface, says Javnozon. Manufacturers have often spent a lot of time and money developing their own signature user interfaces. NavReady has been designed to work in the background with these interfaces, he says.
The output of a system is determined by ONE constraint
The Theory of Constraints (TOC) is a management philosophy developed by Dr. Eliyahu Moshe Goldratt. According to Goldratt the strength of any chain, process, or system is dependent upon its weakest link. TOC is systemic and strives to identify constraints to system success and to effect the changes necessary to remove them. Dr. Goldratt and the TOC became widely known with the 1984 publication of Goldratt's novel The Goal.
DOWNLOAD1-A Review of Goldratt’s Theory of Constraints (TOC) – lessons from the international literature
DOWNLOAD8-Goldratt's "Theory of Constraints" Thinking Processes: A Systems Methodology linking Soft with Hard
HISTORY
In early 1979 Goldratt introduced a software-based manufacturing scheduling program known as Optimized Production Timetables (OPT), changed in 1982 to Optimized Production Technology. With the publication of The Goal, Goldratt used his Socratic teaching style to educate the world about managing bottlenecks (constraints) and his new ideas about performance. The Goal, is a love story set in the manufacturing industry (thrice revised) detailing the tribulations of a plant manager named Alex Rogo. Rogo is faced with the shutdown of his hometown manufacturing plant. Goldratt uses Rogo's predicament to introduce his principles, which result not only in the rescue of Rogo's plant, but also in the salvation of Rogo's marriage. Goldratt himself appears in the book as a character known as Jonah, Rogo's old college professor.
Goldratt used three additional novels to refine and develop the principles set forth in The Goal. It's Not Luck, a sequel to The Goal, addresses changing markets and introduces a number of methods of logical thinking that are used to make decisions, solve problems, and resolve conflict. The Critical Chain depicts a situation whereby TOC principles are effectively utilized in project management. Necessary But Not Sufficient contains Goldratt's most holistic expression of TOC and deals with the role of technology in organizations.
Goldratt also produced a number of nonliterary works that espouse his ideas. The Race, introduced the concept of the drum-buffer-rope and buffer management. Essays on the Theory of Constraints, What Is This Thing Called Theory of Constraints and How Should It Be Implemented? and The Haystack Syndrome: Sifting Information Out of the Data Ocean were used, among other publications, to introduce the thinking processes and other TOC concepts.
COMPONENTS OF THE THEORY OF CONSTRAINTS
Theory of constraints consists of separate, but related processes and interrelated concepts, including the following: the performance measures and five focusing steps, logical thinking processes, and logistics.
PERFORMANCE MEASURES.
According to Goldratt there are three key performance measurements to evaluate: throughput, inventory and operating expense. TOC emphasizes the use of these three global operational measures rather than local measures (e.g., efficiency and utilization). Goldratt places the greatest importance on increasing throughput. Throughput is defined as the rate at which the system generates money through sales, not through production. Goods are not considered an asset until sold. This contradicts the common accounting practice of listing inventory as an asset even if it may never be sold. Goldratt has advocated a new accounting model as an alternative to traditional cost accounting procedures and measures. Inventory is defined as the money invested in goods that the firm intends to sell or material that the firm intends to convert into salable items. The concept of value-added and overhead are not considered. Operating expense includes all the money the firm spends converting inventory into throughput. The objective of the firm, therefore, is to increase throughput and/or decrease inventory and operating expense in such a way as to increase profit, return on investment, and cash flow (more global measures). In The Goal, Alex explains to Jonah that his plant's use of a robot has resulted in a thirty six percent improvement in one area. Jonah then asks if Alex is now able to ship more products, and if he has fired any employees or reduced inventory as a result (in other words, whether increased throughput, reduced operating expense, or reduced inventory resulted). When the reply was no, Jonah questions how there can be any real improvement; and of course, there can't.
Increasing throughput and/or decreasing inventory or operating expense should lead to the accomplishment of the firm's goal: to make money now as well as in the future. Anything that prevents a firm from reaching this goal is labeled as a constraint. Constraints may appear in the form of capacity, material, logistics, the market (demand), behavior, or even management policy. TOC thinking regards all progress toward the goal of making money as relating directly to management attention toward the constraint(s). The marginal value of time at a constraint resource is said to be equal to the throughput rate of the product processed at the constraint, while the marginal value of time at a nonconstraint resource is said to be negligible.
FIVE FOCUSING STEPS.
The five focusing steps are a tool Goldratt developed to help systems deal with constraints. These steps ensure improvement efforts remains on track towards system-level improvements. Dettmer believes that these are collectively the most important aspect of TOC. TOC's five focusing steps are:
Step 1: Identify the system's constraint(s).
Step 2: Decide how to exploit the system's constraint(s).
Step 3: Subordinate everything else to the decisions made in Step 2.
Step 4: Elevate the system's constraint(s)
Step 5: If a constraint is broken in Step 4, go back to Step 1, but do not allow inertia to cause a new constraint.
The orientation of TOC is toward the output of the entire system, rather than a look at a discrete unit or component. The five focusing steps assist with identifying the largest constraint that overshadows all of the others. These steps constitute an iterative process. As soon as one constraint is strengthened, the next weakest link becomes the priority constraint and should be addressed. Thus, a process of ongoing system improvement is applied to the business practice of the firm.
LOGICAL THINKING PROCESS.
Goldratt introduced a staged logical thinking process to be used in conjunction with the five focusing steps. The thinking process assists with working through the change process by identifying the following: what to change, what to change to, and how to effect the change. The thinking processes consist of logic tools used to identify problems, then develop and implement solutions. These tools include effect-cause-effect (ECE) diagramming and its components: negative branch reservations, the current reality tree, the future reality tree, the prerequisite tree, the transition tree, the evaporating cloud, the negative branch reservation, and the ECE audit process. These tools allow an organization to analyze and to verbalize cause and effect.
The following is a brief description of the thinking process. A current reality tree, a cause-effect diagram, is drawn in order to discover the problems. These problems are known as undesirable effects. The cause of an undesirable effect is known as a root cause. The first goal is to find the causes of these undesirable effects. Each statement in a current reality tree that is not a derivative of another must be a root cause. If you build a tree that is comprehensive enough, at least one root cause will lead to most of the undesirable effects. This particular root cause is labeled a core problem, the major improvement target. The fewer root causes responsible for the undesirable effects, the better. The solution to this core problem is apparently not readily available. If it were, then the problem would have already been solved. Some conflict, therefore, must exist that prevents an immediate solution. This conflict becomes evident upon the construction of an evaporating cloud.
An evaporating cloud is a conflict-resolution tool. The process begins with a statement of the desired objective, one that is the opposite of the core problem. Then, the prerequisites necessary to achieve the requirements are listed. Any conflicts and assumptions that exist between the prerequisites are verbalized. For example, if one objective is to increase profit, then the requirements may be to improve the product and to decrease expenses. Prerequisites for each, respectively, might be to increase expenditures on capital equipment and to decrease expenditures, two obviously conflicting elements. The best solution is to remove the conflict; a compromise is not desirable. The next move involves finding an injection, a breakthrough idea that will evaporate the cloud. The "evaporating" refers to the tool's ability to dissipate conflict and to create a win-win solution. Usually, the original injection is not sufficient to fully solve the problem, but additional needed injections become clear when building the future reality tree.
A future reality tree is another cause-effect diagram. The tree starts with the proposed solution to the core problem and delineates the injection(s) and the ensuing desirable effects. The future reality tree is a "what if." It provides the opportunity to evaluate and to improve a solution before it is implemented. It is noted that one should be careful not to allow the solution to cause new undesirable effects.
A prerequisite tree describes the implementation of the injection(s) and is composed of an obstacle and an intermediate objective. This diagram breaks the implementation tasks into smaller increments, noting expected obstacles and intermediate objectives whose accomplishments will overcome the obstacles. The intermediate objectives are sequenced, displaying the necessary order of accomplishment and determining which ones can be achieved in parallel. This tool is powerful in that it does not ignore the obstacles. It uses them, rather, as the main vehicle for this phase.
Finally, a transition tree or implementation plan is constructed. This element presents a detailed description of the gradually evolving change envisioned. This task forces one to carefully examine which actions are really needed and if they are sufficient to guarantee the required change.
The thinking-process tools are powerful resources when used effectively. They have found successful use in the logistics and medicine areas of the United States Air Force, in primary education, and in the service sector. James Cox and Michael Spencer, both college professors and "Jonahs," state in The Constraints Management Handbook that the thinking processes may be the most important management tools developed this century.
LOGISTICS.
Logistics in TOC include drum-buffer-rope scheduling, buffer management, and VAT analysis.
DRUM-BUFFER-ROPE.
Drum-buffer-rope is a TOC production application and the name given to the method used to schedule the flow of materials in a TOC facility. Srikanth and Umble (1997), define each component as follows:
Drum. The drum is the constraint and therefore sets the pace for the entire system. The drum must reconcile the customer requirements with the system's constraints. In simpler terms, the drum is the rate or pace of production set by the system's constraint.
Buffer. A buffer includes time or materials that support throughput and/or due date performance. A buffer establishes some protection against uncertainty so that the system can maximize throughput. A time buffer is the additional planned lead time allowed, beyond the required setup and run times, for materials to reach a specified point in the product flow. Strategically placed, time buffers are designed to protect the system throughput from the internal disruptions that are inherent in any process. A stock buffer is defined as inventories of specific products that are held in finished, partially finished, or raw material form, in order to fill customer orders in less than the normal lead-time. Stock buffers are designed to improve the responsiveness of the system to specific market conditions.
Rope. The rope is a schedule for releasing raw materials to the floor. The rope is devised according to the drum and the buffer. The rope ensures that non-capacity constraint resources are subordinate to the constraint. Restated, the rope is a communication process from the constraint to the gating operation that checks or limits material released into the system to support the constraint.
BUFFER MANAGEMENT.
Buffer management provides the means by which the schedule is managed on the shop floor. Buffer management is a process in which all expediting in a shop is motivated by what is scheduled to be in the buffers (constraint, shipping, and assembly buffers). Buffers can be maintained at the constraint, convergent points, divergent points, and shipping points. By expediting this material into the buffers, the system helps to avoid idleness at the constraint and missed customer due dates. Also, the causes of items missing from the buffer are identified, and the frequency of occurrences is used to prioritize improvement activities.
VAT ANALYSIS.
VAT analysis determines the general flow of parts and products from raw materials to finished products. It conceptualizes an organization in terms of the interaction of its individual component parts, both products and processes. Three general categories of production structures result from this standpoint, each necessitating a unique approach to management planning and control. The logical structure is the sequence of operations through which each product must pass in order to manufacture and assemble a product or product family. A V logical structure starts with one or a few raw materials, and the product
expands into a number of different products as it flows through its routings. The shape of an A logical structure is dominated by converging points. Many raw materials are fabricated and assembled into a few finished projects. A T logical structure consists of numerous similar finished products assembled from common assemblies and subassemblies. The graph shows the general appearance of each structure. Once the general parts flow is determined, the system control points (gating operations, convergent points, divergent points, constraints, and shipping points) can be identified and managed. This determination focuses management's attention on a few control points where buffers can be used to protect and to maximize throughput. Five control points are used to manage the process: (1) the constraint, (2) the points of divergence (where a part or material is diverted to different routes in order to make different products), (3) the points of convergence (where two or more parts are combined in subassembly), (4) the gating operation (releases work into the shop), and (5) the shipping operation.
The shape of the structure determines which control points are utilized to manage production. A T structure focuses attention on the constraint and the gating operation. The five-step focusing process is used to manage the constraint with a buffer placed before the constraint to absorb variations in the process. The output from the gating operation is tied to the constraint; that is, since the constraint controls the amount of throughput; the gating operation cannot process more than the constraint.
A V structure also uses a buffer to protect the constraint and the gating operation releases orders at the same rate as the constraint as seen in the T structure. However, an additional control point exists in the V structure, the divergent point. The divergent point is controlled by a schedule derived from the shipping schedule. This derivation prevents misallocation of material to a product not currently in demand.
The A structure also manages the constraint and gating operation in a fashion similar to the T structure. Any diverging points are scheduled in accordance with the shipping schedule. In addition, an assembly buffer is used to maintain the flow into the convergent points. An additional schedule based on the shipping schedule (similar to that used in the V structure) is used to keep capacity from being misallocated to the wrong order. By using VAT analysis, significant improvements in the production process can result.
The unexpected and enormous success of The Goal, initially published in a small run of 3,000 copies and has now sold more than 2 million copies, and further development of TOC has lead many organizations to put TOC theory into practice. Over the past two decades a growing number of books, articles, and dissertations have appeared elaborating on Dr. Goldratt's philosophy and providing examples of TOC principles in use. Followers of Goldratt's philosophy, those who have completed an extensive training course conducted by Goldratt's educational firm, the Avraham Y. Goldratt Institute, refer to themselves as Jonahs. TOC materials are available in multiple languages and formats, including videotapes, audiotapes, and computer software.
Cox, James F., and Michael S. Spencer. The Constraints Management Handbook. Boca Raton, FL: St. Lucie Press, 1998.
Dettmer, H. William. Goldratt's Theory of Constraints: A Systems Approach to Continuous Improvement. Milwaukee, WI: ASQC Quality Press, 1997.
Dugdale, David, and Colwyn Jones. "Accounting for Throughput: Techniques for Performance Measurement, Decisions and Control." Management Accounting 75, no. 11 (1997): 52–56.
Essays on the Theory of Constraints. Great Barrington, MA: The North River Press, 1990.
Gardiner, Stanley C., John H. Blackstone, and Lorraine R. Gardiner. "The Evolution of the Theory of Constraints." Industrial Management 36, no. 3 (1994): 13–16.
Goldratt, Eliyahu M. Critical Chain. Great Barrington, MA: The North River Press, 1997.
——. Haystack Syndrome: Sifting Information Out of the Data Ocean. Croton-on-Hudson, NY: North River Press, 1990.
——. It's Not Luck. Croton-on-Hudson, NY: North River Press, 1994.
——. Late Night Discussions on the Theory of Constraints. Great Barrington, MA: The North River Press, 1992.
——. "What is the Theory of Constraints?" APICS: The Performance Advantage, June 1993, 18–20.
——. What Is This Thing Called Theory of Constraints and How Should It Be Implemented? Croton-on-Hudson, NY: North River Press, 1990.
Goldratt, Eliyahu M., Eli Schragenheim, and Carol A. Ptak. Necessary But Not Sufficient: A Theory of Constraints Business Novel. Great Barrington, MA: The North River Press, 2000.
Goldratt, Eliyahu M., and Jeff Cox. The Goal: A Process of Ongoing Improvement. 3rd ed. Great Barrington, MA: The North River Press, 2004
——. The Goal: A Process of Ongoing Improvement. 2nd ed. Croton-on-Hudson, NY: The North River Press, 1994.
——. The Goal: Excellence in Manufacturing. Croton-on-Hudson, NY: The North River Press, 1984.
Goldratt, Eliyahu M., and Robert E. Fox. The Race. Croton-on-Hudson, NY: The North River Press, 1986.
Kendall, Gerald I. Securing the Future: Strategies for Exponential Growth Using the Theory of Constraints. Boca Raton, FL: St. Lucie Press, 1998.
Mabin, Victoria, J., and Steven J. Balderstone. The World of the Theory of Constraints: A Review of the International Literature. Boca Raton, FL: St. Lucie Press, 2000.
McMullen, Thomas B., Jr. Introduction to the Theory of Constraints (TOC) Management System. Boca Raton, FL: St. Lucie Press, 1998.
Newbold, Robert C. Project Management in the Fast Lane: Applying the Theory of Constraints. Boca Raton, FL: St. Lucie Press, 1998.
Noreen, Eric, Debra Smith, and James T. Mackey. The Theory of Constraints and its Implications for Management Accounting. Great Barrington, MA: The North River Press, 1995.
Rahman, Shams-ur. "Theory of Constraints: A Review of the Philosophy and Its Applications." International Journal of Operations and Production Management 18, no. 4 (1998): 336–355.
Scheinkopf, Lisa J. Thinking for a Change: Putting the TOC Thinking Processes to Use. Boca Raton, FL: St. Lucie Press, 1999.
Schragenheim, Eli, and H. William Dettmer. Manufacturing at Warp Speed: Optimizing Supply Chain Financial Performance. Boca Raton, FL: St. Lucie Press, 2001.
Smith, Debra. The Measurement Nightmare: How the Theory of Constraints Can Resolve Conflicting Strategies, Policies, and Measures. Boca Raton, FL: St. Lucie Press, 2000.
Srikanth, Mokshagundam L., and Harold E. Cavallaro, Jr. Regaining Competitiveness: Putting 'The Goal' To Work. New Haven, CT: The Spectrum Publishing Company, 1987.
Srikanth, Mokshagundam L., and Michael M. Umble. Synchronous Management: Profit-Based Manufacturing for the 21st Century. 2 vols. Guilford, CT: The Spectrum Publishing Company, 1997.
Stein, Robert R. Reengineering the Manufacturing System: Applying the Theory of Constraints. 2nd ed. New York: Marcel Dekker, Inc., 2003.
Woeppel, Mark J. The Manufacturer's Guide to Implementing the Theory of Constraints. Boca Raton, FL: St. Lucie Press, 2001.
Womack, David E., and Steve Flowers. "Improving System Performance: A Case Study in the Application of the Theory of Constraints." Journal of Healthcare Management 44, no. 5 (1999): 397–407.
Theory of Constraints (TOC): Engpasssteuerung in Industriebetrieben
Theory of Constraints (TOC): Engpasssteuerung in Industriebetrieben
Die Wertschöpfungskette der meisten Produktionsunternehmen setzt sich aus verschiedenen Herstellungsprozessen zusammen. Dabei wurden die Fertigungskapazitäten in der Vergangenheit oft punktuell angepasst. Viele Produktionen sind so organisch gewachsen. Die Folgen sind oft ein suboptimales Fertigungslayout mit langen Transportwegen, ein schlechter Materialfluss und aufeinander unabgestimmte Kapazitätsquerschnitte von Maschinen und Anlagen. Die Unternehmen spüren diese Folgen anhand steigender Durchlaufzeiten, steigenden Umlaufbeständen von Rohmaterialen und Halbfertigteilen sowie einer sinkenden Liefertreue. Um hier Abhilfe zu schaffen, wurden oft die einzelnen Fertigungsprozesse nach betriebswirtschaftlichen Gesichtspunkten optimiert. Eine ganzheitliche Analyse der Wertschöpfungskette mit einer anschließenden Optimierung anhand der Engpässe wurde jedoch selten in Betracht gezogen.
Theory of Constraints als systemische Grundlage zur Fertigungsoptimierung
Zur ganzheitlichen Optimierung der Fertigungskapazitäten entlang der Wertschöpfungskette hat sich die Theory of Constraints (TOC) sehr gut gewährt. TOC geht von der Systemtheorie der Kybernetik aus. Ein System besteht dabei aus Elementen die in gegenseitiger Wechselwirkung zueinander stehen, jedoch klar voneinander abgegrenzt sind. Nach der TOC wächst ein System so lange, bis es durch einen Engpass begrenzt wird. Für die Identifikation des Engpasses ist eine systemweite Analyse notwendig, da sonst die Interdependenzen der einzelnen Elemente nicht vollständig berücksichtigt werden. Bei einer Analyse und Optimierung eines Teilsystems besteht sonst die große Gefahr, dass Leistungsfähigkeit des Gesamtsystems leidet.
Wertschöpfungsoptimierung in 5 Schritten
Die Identifikation von Engpässen in einer Wertschöpfungskette sowie die Steuerung und Optimierung erfolgt in fünf Schritten:
1. Schritt: Identifikation der Engpässe und Klassifizierung Die Kapazitätsquerschnitte aller Prozesse der Wertschöpfungsketten werden analysiert. Als Messgröße dient hierbei der Durchsatz der zu produzierenden Teile je Zeiteinheit. Die Zeiteinheit ist in Abhängigkeit des Arbeitszeitmodells so zu wählen, dass sie über die gesamte Wertschöpfungskette konstant ist. Üblicherweise ist dies eine Schichtdauer. Abschließend werden die Engpässe nach aufsteigenden Kapazitätsquerschnitten sortiert, so dass an erster Stelle der größte Engpass steht. Dieser Engpass ersten Grades ist nun Betrachtungsgegenstand für alle nachfolgenden Optimierungsmaßnahmen.
2. Schritt: Maximale Ausnutzung des Engpasses Da der Engpass den maximalen Durchsatz für die gesamte Wertschöpfungskette bestimmt, ist dieser nun maximal auszunutzen. In der Praxis bedeutet dies, dass beispielsweise Stillstandzeiten durch Rüstzeitoptimierung zu minimieren sind.
3. Schritt: Alles dem Engpass unterordnen Für eine maximale Ausnutzung sind alle übrigen Fertigungsprozesse dem Engpass unterzuordnen. Die Prioritäten können auch teilweise so verschoben werden, dass andere Fertigungsprozesse hierdurch unwirtschaftlicher werden. Wird beispielsweise die Losgröße für den Engpass optimiert, kann dies zu Produktivitätsverlusten in anderen Fertigungsschritten führen. Dennoch kann hierbei die Gesamtproduktivität der Wertschöpfungskette steigen.
4. Schritt: Engpass verbreitern Ein großer Engpass verhindert eine ganzheitliche wirtschaftliche Produktion. Der Engpass ist in diesem Fall zu verbreiten. Ist der Engpass beispielsweise eine Maschine so stehen für die Erweiterung des Kapazitätsquerschnitts generell zwei Möglichkeiten zur Verfügung. Die erste Möglichkeit ist die Anschaffung einer weiteren Maschine. Bei der zweiten Möglichkeit ist zu prüfen, inwieweit der Prozessschritt zu einem externen Dienstleister gegeben werden kann und Teile künftig außer Haus gefertigt werden können.
5. Schritt: Wiederholung der Prozedur bei Schritt 1 Nach Durchführung der vorangegangenen Optimierungsschritte wird erneut mit dem ersten Schritt Identifikation der Engpässe und Klassifizierung begonnen. Hierbei kann es sein, dass nun ein anderer Prozess den Engpass ersten Grades darstellt, der dann entsprechend zu optimieren ist.
Das iterative TOC-Verfahren lässt sich beliebig oft anwenden. Dabei ist eine lückenlose Dokumentation der durchgeführten Optimierungsmaßnahmen unerlässlich. Ansonsten besteht die Gefahr, das zwischen den gleichen zwei oder drei Engpässen hin- und heroptimiert wird, ohne dass eine Nachhaltige Aufweitung der Kapazitätsquerschnitte statt findet.
Verbesserungen durch die Theory of Constraints
Die hier vorgestellte Vorgehensweise zur Engpasssteuerung und -optimierung hat sich in der Vergangenheit insbesondere in den Bereichen Logistik und Fertigungssteuerung bewährt. In der jüngsten Vergangenheit wurde das TOC-Verfahren verstärkt im Vertrieb eingesetzt. Beispiele für die Anwendung von TOC sind die Erschließung neuer Märkte oder die Segmentierung bestehender Märkte. Gerade Vertriebssysteme sind durch Managemententscheidungen besonders anfällig für das Entstehen von Engpässen. Durch eine konsequente Anwendung von TOC können die Umsätze deutlich gesteigert werden. Weitere Anwendungsfelder sind die Produktentwicklung, die strategische Planung oder das Pipeline Management.
Die größte Wirkung der konsequenten Anwendung der TOC Methode liegt in der Steigerung der Umsätze (bis zu 76%) und der Reduzierung der Durchlaufzeiten (bis zu 70%). Weitere Potentiale erschließen sich durch eine Reduzierung der Zykluszeiten und der Bestände sowie bei der Steigerung der Lieferperformance und des Produktionsdurchsatzes.
Generally constructed of plastic, metal, or wood, a pallet is a piece of transportation/movement equipment utilized in the movement of unit loads. Usually "fork-liftable" in that it is designed to accept forks between the top and bottom platforms of the unit.STANDARD
Pallet Dimensions Measurement points to determine a pallet's dimensions: Length = distance between pallet ends (inclusive of overhang) and parallel to the stringer(s). Width = distance between pallet sides at right angles to the pallet length inclusive of any overhang. Height = distance from the outer edges of the bottom deck boards to the outer edges of the top deck board. Pallet dimensions are generally shown in inches.
Euro Pallet The standard pallet in Europe. It is 1200 mm by 800 mm in dimension and has a wood block design between the top and bottom permitting four-way or four-sided entrance by lifting forks. Although other sizes exist in Europe, they are not nearly as prominent as the Euro-pallet.DIETAIL.
Name
Dimensions (mm)
Pallet EUR
800 x 1200 fits through many doors
Pallet EUR 2
1200 x 1000
Pallet EUR 3
1000 x 1200
Pallet EUR 6
800 x 600
Pallet Pattern The layer-by-Ayer arrangement or pattern of boxes/cartons as they are placed on a pallet.
Pallet Performance The performance of a pallet as expressed in terms of durability, stability (lateral), degree of stiffness or rigidity, and strength.
Palletizer Palletizers are special machines capable of building a complete unit load on a pallet. Although the most common application is for cases, some palletizers can also handle sacks and bags. A less common palletizer application would be for special products such as sheet stock. There are two general methods employed for automatically building a full pallet. One makes use of a fixed position or overhead gantry robot with end effectors suited to the individual loads, such as vacuum lifts or a gripper. The other method employs more complex mechanisms for forming pallet layers off line, one at a time, and then shifting or transferring each successive layer onto the pallet as it is lowered via a lift/lower table.
Reversible Pallet
A pallet designed and constructed to use both the top and bottom deck boards as load bearing members.
Throwaway Pallet A pallet whose planned usage is limited to one use and then is discarded.
All-way Entry Pallet The construction of the pallet allows entry from all sides and ends by a fork truck.
Bin Pallet A four-sided superstructure that is mounted on a pallet base, with or without a cover. Also known as a box or container bin pallet.
Cross Docking The process of moving merchandise from the receiving dock to shipping for shipping without placing it first into storage locations. Information regarding the merchandise will be entered into the inventory and a transaction for shipping posted within one posting cycle, e.g. one day.
General Purpose Pallet A pallet that is designed and constructed for general use and is returnable. This pallet is generally double decked in its construction.
ISO pallets
Dimensions (mm)
Dimensions (inches)
Wasted floor, ISO Container
Region
1219 x 1016
48.00 x 40.00
3.7%
North America
1200 x 1000
47.24 x 39.37
6.7%
Europe, Asia; similar to 48x40".
1140 x 1140
44.88 x 44.88
8.1%
Australia
1067 x 1067
42.00 x 42.00
11.5%
North America, Europe, Asia
1100 x 1100
43.30 x 43.30
14%
Asia
1200 x 800
47.24 x 31.50
15.2%
Europe; fits many doorways
Block pallet
Block pallets (also referred to as Manoj pallets) are typically stronger than stringer pallets. Block pallets utilize both parallel and perpendicular stringers to better facilitate efficient handling. A block pallet is also known as a "four-way" pallet, since a pallet-jack may be used from any side to move it.
Stringer pallet
Stringer pallets use a frame of three parallel pieces of timber (called stringers). The top deckboards are then affixed to the stringers to create the pallet structure. Stringer pallets are also known as "two-way" pallets, since a pallet-jack may only lift it from two directions instead of four. Forklifts can lift a stringer pallet from all four directions, though lifting by the stringers is more secure.
Study: Americans use Net to look beyond sound bite
By Associated Press
NEW YORK (AP) _ Americans dissatisfied with political sound bites are turning to the Internet for a more complete picture, a new study finds.
In a report Sunday, the Pew Internet and American Life Project said that nearly 30 percent of adults have used the Internet to read or watch unfiltered campaign material -- footage of debates, position papers, announcements and transcripts of speeches.
"They want to see the full-blown campaign event. They want to read the speech from beginning to end," said Lee Rainie, director of the Pew group. "It's a push back from the sound-bite culture."
Google Inc.'s YouTube and other video sites have become more popular. Thirty-five percent of adults have watched a political video online during the primary season, compared with 13 percent during the entire 2004 presidential race.
The study also found that 10 percent of adults have used online hangouts like Facebook and News Corp.'s MySpace for political activity, whether it's to add a campaign as a friend on their personal profile pages, discover a friend's political interests or join an online political group.
Of course, video and social networking have grown in general since the last presidential election.
"It is mirroring the broader trends that we see online," Rainie said.
Pew also found online fundraising is up -- 6 percent of adults have contributed to a campaign using the Internet, compared with 2 percent in 2004.
The Internet has allowed campaigns to reach first-time donors without the expense of direct mail or phone calls. Democrat Barack Obama has been particularly adept at generating small donations from a vast number of Internet users to become the fundraising leader among all the presidential candidates.
Pew found that among Internet users, Obama supporters were about twice as likely as backers of Democratic rival Hillary Rodham Clinton and Republican John McCain to have made a campaign contribution online.
All told, 46 percent of Americans have used the Internet or cell phone text messaging for some political activity.
Yet they have mixed views about the Internet in politics. Sixty percent of Internet users fear that misinformation and propaganda are widespread online and that too many other voters are trusting that information. And only 28 percent believe the Internet helps them feel more personally connected to the candidate they support.
The telephone study of 2,251 adults, including 1,553 Internet users, was conducted April 8 to May 11 and has a margin of sampling error of plus or minus 2 percentage points.
A technique for saving bandwidth in Internet phone calls could undermine their security, according to research recently presented at the IEEE Symposium on Security and Privacy. Johns Hopkins University researchers showed that, in encrypted phone calls using a certain combination of technologies, preselected phrases can be spotted up to 50 percent of the time on average, and up to 90 percent of the time under optimal conditions.
Voice-over-Internet-protocol (VoIP) phone calls, in which a computer converts a voice signal into data packets and sends them over the Internet, are increasingly popular for personal and business communication. Although most VoIP systems don't yet use encryption, says Jason Ostrom, director of the VoIP-exploitation research lab at Sipera Systems, it's absolutely necessary, particularly for business users. In many cases, security measures aren't in place because companies haven't realized how vulnerable VoIP can be, he says. He cites an assessment that he did for a hotel that uses VoIP phones, in which he showed that an attacker could access and record guests' calls using a laptop plugged into a standard wall connection. The Johns Hopkins researchers hope that pointing out possible holes in voice encryption systems can help ensure their security when they become more commonplace.
The Johns Hopkins attack takes advantage of a compression technique called variable-bit-rate encoding, which is sometimes used to save bandwidth in VoIP calls, explains Charles Wright, lead author of the paper. (Wright, who recently received his PhD from Johns Hopkins, will join the technical staff at the MIT Lincoln Laboratory in August.) Variable-bit-rate encoding, Wright says, adjusts the size of data packets being sent over the Internet based on how much information they actually contain. For example, when the person on one end of a VoIP call is listening rather than speaking, the packets sent from that person's computer shrink significantly. Also, packets containing certain sounds, such as "s" or "f," can take up less space than those containing more-complex sounds, such as vowels.
Encrypting the packets after they've been compressed scrambles their contents, making them look like gibberish. But it doesn't change their size, which is what would give away information to potential eavesdroppers.
Bandwidth savings, security loss: Eavesdroppers could listen for specific phrases in encrypted phone calls sent over the Internet, if the calls use a bandwidth-savings tool called variable-bit-rate encoding. Different sounds produce different quantities of information. At right, that difference can be seen in the sounds’ energy distributions across a range of frequencies. With variable-bit-rate encoding, different quantities of information yield different-sized data packets, represented at left as color coding across the audio waveform. An eavesdropper could listen for particular phrases by looking for patterns in the sizes of consecutive packets. Credit: Charles Wright/Johns Hopkins University
Encrypting the packets after they've been compressed scrambles their contents, making them look like gibberish. But it doesn't change their size, which is what would give away information to potential eavesdroppers.
In their tests, the Hopkins researchers simulated the packets that a combination of compression and encryption would produce for particular phrases. While an example of the way that a targeted speaker pronounced a particular phrase would give eavesdroppers a big advantage, they could still simulate the phrase using a pronunciation dictionary and a database of sample sounds from multiple speakers. The researchers can create many versions of the sounds in the phrase, which lets them accommodate different accents and other variations in pronunciation. They then use probabilistic methods to look for likely instances of the phrase. Wright says that the method can identify the phrase, on average, about half the time that it occurs, and that about half of the phrases it flags turn out to be exact matches of the desired phrase. In some circumstances, as when the phrases are longer, or when the speakers are particularly well matched to the simulated versions of the phrase, the accuracy became as high as 90 percent, Wright says. Because eavesdroppers have to know what phrase they're listening for, Wright says, "the threat would be more to technical, professional jargon than to an informal call between friends or family members."
While 50 percent accuracy may not sound like much, "these are encrypted conversations, so your expectation is not to be able to do this at all," says Fabian Monrose, an associate professor of computer science at Johns Hopkins, who was also involved in the research.
Matt Bishop, a professor of computer science at the University of California, Davis, agrees. "Fifty percent is quite scary," he says, "because what it means is that, in essence, you could potentially understand a fair portion of the conversation. The whole purpose of encryption is to prevent understanding." He adds that the attack is made more realistic by its ability to simulate phrases from standard sample sounds, which would be easier for an attacker to obtain than speech samples from the person he or she wants to spy on.
Sipera Systems' Ostrom says that he found the research particularly interesting "because it shows that you shouldn't feel safe just because you're using a security control. You still have to validate it to ensure that it meets your requirements." He adds, "In VoIP, there's always a fight between quality of service and security." The researchers' attack is a good example, he says, because it explores how an effort to improve quality of service by reducing bandwidth usage can affect efforts to protect calls. However, Ostrom notes that most corporations aren't currently using variable-bit-rate encoding and wouldn't now be at risk.
Wright and Monrose say that they see their work as more of a cautionary tale. Monrose says that recently he has been seeing drafts of technical specifications that call for variable-bit-rate encoders. "Our gut reaction was, this has privacy implications that people have not well studied," he says. The researchers say that they hope their work will prevent people from making design decisions in isolation and encourage them to think about solutions that will increase both efficiency and security. "If we start combining tools the way a lot of the specifications are calling for," Monrose says, "then we need to make sure that we do it in the right way."
WHAT are the implications of rising bond yields for equity markets? Answering this question requires grappling with one of the most fundamental debates in modern finance.
One approach sees equities and bonds as assets that compete for a place in investors' portfolios. If one asset class becomes overpriced, then investors will flock to the other. The conventional way of comparing the two is to look at the yields.
But which equity yield? In more conservative times, investors looked at the dividend yield. Until the late 1950s, it was common for the dividend yield on the stockmarket to be higher than the government-bond yield; after all, since dividends could be cut, they were more risky.
But pension funds and other institutional investors noted that, in a broadly diversified portfolio, dividends would tend to rise pretty steadily over time. That growth meant that equities could trade at a lower dividend yield than bonds. The wisdom of this shift into equities seemed to be confirmed when the real value of bonds was devastated by the inflation of the 1960s and 1970s.
By the 1990s, investors had turned to the earnings yield, the inverse of the price-earnings ratio (so if the p/e is 20, the earnings yield is 5%). A paper by Federal Reserve economists led to a widespread belief in the Fed model—that the market was fairly priced when the prospective earnings yield on the stockmarket was equivalent to the ten-year Treasury-bond yield.
In this world, falling bond yields were seen as unequivocally good news for equities. And it seemed to work, thanks to the long period of disinflation from 1982 onwards, which saw nominal bond yields fall sharply and share prices rise substantially.
Believing in this model, however, required one to ignore some powerful contrary bits of evidence. After all, the model did not work prior to 1960. Companies only pay out a fraction of their earnings as dividends, so the earnings yield was then much higher than the government-bond yield. And the model did not work in 1990s Japan, where sharply falling government-bond yields were no help to the stockmarket.
Disillusionment came in 2000-02. Bond yields fell sharply, but this was not good news for shares. Indeed, investors were switching out of shares and into fixed income in the wake of the dotcom bubble. Equities looked cheap on the basis of the Fed model and got cheaper. A lot of people argued that the model was rubbish; after all, if lower bond yields were the result of lower inflation, then why should equities benefit? Profits forecasts would have to fall as well.
The answer to the riddle seems to show up in some figures (see chart) highlighted by Richard Cookson, a strategist at HSBC (and a former writer for The Economist). Bonds may move in sync with equities at some parts of the economic cycle but not at others. When recession or deflation looms, government bonds are relatively unaffected but equities suffer because profits are likely to fall.
Since 1900, when inflation has been in the 1-4% range, price-earnings ratios on the stockmarket have averaged between 17 and 19; in other words, an earnings yield of 5-6%. But when inflation has been below 1%, p/e ratios have averaged just 14 (an earnings yield of 7%). In such circumstances, bond yields fall but earnings yields rise.
In the current situation, bond yields are rising because of inflation: the headline rate is above 4% in Britain and America. And that is a problem for equities, since 4% seems to be a key figure. Average p/es when inflation has been in the 4-5% range have been 15; by the time inflation reaches 6-7%, the p/e drops to 11.
The problem for stockmarket investors is that the economy currently seems posed between extremes. If inflation returns, that will be bad for valuations; if recession wins out, that will be bad for profits. It is an unpalatable choice.
China gets most foreign direct investment among developing countries, but its share is falling
DEVELOPING countries are attracting more foreign investment than ever before. Since 2000, FDI inflows have rocketed from $165.5 billion to an estimated $470.8 billion in 2007 says the World Bank. China draws the most, attracting $84 billion of investment last year. But this represented 18% of the total compared with 30% five years before. By contrast, Brazil and Turkey have seen their share increase. Investment has poured into Russia, mainly because of its energy boom, even despite increasing regulatory hurdles to foreign investors. Mexico is the fourth-biggest destination country, receiving $23.2 billion in FDI—the same as it gets in remittances.
Champions aren't made in gyms, champions are made from something they have deep inside them - a desire, a dream, a vision. They have to have last-minute stamina, they have to be a little faster, they have to have the skill and the will. But the will must be stronger than the skill. -Muhammad Ali I'll be more enthusiastic about encouraging thinking outside the box when there's evidence of any thinking going on inside it. - Terry Pratchett Not to be absolutely certain is, I think, one of the essential things in rationality. - Bertrand Russell What we think, or what we know, or what we believe is, in the end, of little consequence. The only consequence is what we do. Sometimes what's right isn't as important as what's profitable. - Trey Parker and Matt Stone There are only two kinds of people who are really fascinating: people who know absolutely everything, and people who know absolutely nothing. - Oscar Wilde Sometimes I lie awake at night, and I ask, "Where have I gone wrong?"/ Then a voice says to me, "This is going to take more than one night." - Charles M. Schulz There is nothing worse than aggressive stupidity. - Johann Wolfgang von Goethe The significance of man is that he is insignificant and is aware of it. - Carl Becker A lie can travel halfway around the world while the truth is putting on its shoes. - Mark Twain "If you know how to spend less than you get, you have the philosopher's stone." So said Benjamin Franklin more than 200 years ago. How much easier it is to be critical than to be correct. - Benjamin Disraeli Of course the game is rigged. Don't let that stop you--if you don't play, you can't win. - Robert Heinlein Ability will never catch up with the demand for it. - Malcolm Forbes No man remains quite what he was when he recognizes himself. - Thomas Mann No man needs a vacation so much as the man who has just had one. - Elbert Hubbard There is no pleasure in having nothing to do; the fun is in having lots to do and not doing it. - Mary Wilson Little Books to the ceiling,/ Books to the sky,/ My pile of books is a mile high./ How I love them! How I need them!/ I'll have a long beard by the time I read them. - Arnold Lobel Leif Ostling said in a statement that his comments about Germany had been "interpreted in a way that was not intended." If a man will begin with certainties, he shall end in doubts; but if he will be content to begin with doubts he shall end in certainties. - Sir Francis Bacon "It's not the voting that's democracy, it's the counting." - Tom Stoppard Elections are won by men and women chiefly because most people vote against somebody rather than for somebody. - Franklin P. Adams Invention is the mother of necessity. - Thorstein Veblen Don't try to solve serious matters in the middle of the night. - Philip K. Dick
Das Loreleylied
Ich weiß nicht was soll es bedeuten Daß ich so traurig bin; Ein Märchen aus alten Zeiten, Das kommt mir nicht aus dem Sinn.
Die Luft ist kühl und es dunkelt, Und ruhig fließt der Rhein; Der Gipfel des Berges funkelt Im Abendsonnenschein.
Die schönste Jungfrau sitzet Dort oben wunderbar, Ihr goldenes Geschmeide blitzet, Sie kämmt ihr goldenes Haar.
Sie kämmt es mit goldenem Kamme Und singt ein Lied dabey; Das hat eine wundersame, Gewaltige Melodei.
Den Schiffer, im kleinen Schiffe, Ergreift es mit wildem Weh; Er schaut nicht die Felsenriffe, Er schaut nur hinauf in die Höh´.
Ich glaube, die Wellen verschlingen Am Ende Schiffer und Kahn; Und das hat mit ihrem Singen Die Lore-Ley getan.
Credit: Technology Review
Die Identifikation von Engpässen in einer Wertschöpfungskette sowie die Steuerung und Optimierung erfolgt in fünf Schritten:
Bandwidth savings, security loss: Eavesdroppers could listen for specific phrases in encrypted phone calls sent over the Internet, if the calls use a bandwidth-savings tool called variable-bit-rate encoding. Different sounds produce different quantities of information. At right, that difference can be seen in the sounds’ energy distributions across a range of frequencies. With variable-bit-rate encoding, different quantities of information yield different-sized data packets, represented at left as color coding across the audio waveform. An eavesdropper could listen for particular phrases by looking for patterns in the sizes of consecutive packets.
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