In mathematical number theory and computer science , a Morton number is a single integer value constructed by interleaving the bits or digits of one or more source numbers. This is often useful for constructing a single hash index from a pair or more of input numbers. In number theory, Morton numbers are useful in proofs, often in examples which map multiple dimensions to one, or vice versa. For example, an infinite 2D grid of integer coordinates can have a single unique Morton number computed for each coordinate, and those Morton numbers give a one to one mapping of the infinite 2D coordinates to a 1D coordinate along the Z order curve Z order curve proving that the infinite number of integer pairs has the same cardinality as the integers. External links http graphics.stanford.edu seander bithacks.html InterleaveTableObvious Bits interleaving in C Category Hash functions Category Number theory ... more details
In the compact disc system, interleaving cross interleaved Reed Solomon error correction Reed Solomon code or CIRC provides error detection and error correction . ref Patent US 4413340 Inventors Odaka K., Sako Y., Iwamoto I., Doi T. Vries L.B. SONY Error correctable data transmission method CIRC Patent filing date May 21, 1980 ref CIRC adds to every three data byte s one redundancy information theory redundant parity bit parity byte. Overview Reed Solomon code s are specifically useful in combating mixtures of random and burst error s. CIRC corrects error burst s up to 3,500 bits in sequence 2.4 mm in length as seen on CD surface and compensates for error bursts up to 12,000 bits 8.5 mm that may be caused by minor scratches. ref Kees Immink K.A.S. Immink , Reed Solomon Codes and the Compact Disc in S.B. Wicker and V.K. Bhargava , Edrs, Reed Solomon Codes and Their Applications , IEEE Press , 1994. ref Characteristics High random error correctability Long burst error correctability In case the burst correction capability is exceeded, interpolation may provide concealment by approximation Simple decoder strategy possible with reasonably sized external random access memory Very high efficiency Room for future introduction of four audio channels without major changes in the format as of 2008, this has not been implemented . Interleave Errors found in the CD system are a combination of random and burst errors. In order to alleviate the strain on the error control code, some form of interleaving is required. The CD system employs two concatenate d Reed Solomon codes, which are interleaved cross wise. Judicious positioning of the stereophonic sound stereo channels as well as the audio samples on even or odd number instants within the interleaving scheme provide the error concealment ability, and the multitude of interleave structures used on the CD makes it possible to correct and detect errors with a relatively low amount of redundancy. References refs See also interleaving ... more details
In computational complexity theory , R is the class of decision problem s solvable by a Turing machine , which is the set of all recursive language s. R is equal to the set of all total computable function s. Since we can decide any problem for which there exists a recogniser and also a co recogniser by simply interleaving them until one obtains a result, the class is equal to math RE cap coRE math . External links CZoo Class R R r Category Complexity classes ComplexityClasses es R clase de complejidad ko R ja R ru R zh R ... more details
distinguish clustered file system Image Disk structure.svg thumb 300px Disk structure br A track br B geometrical sector br C Disk sector track sector br D cluster file system cluster In computer file system s, a cluster is the unit of disk space allocation for files and directories. To reduce the overhead of managing on disk data structures, the filesystem does not allocate individual disk sector s, but contiguous groups of sectors, called clusters. On a disk that uses 512 byte sectors, a 512 byte cluster contains one sector, whereas a 4 kibibyte KiB cluster contains eight sectors. A cluster is the smallest logical amount of disk space that can be allocated to hold a file. Storing small files on a filesystem with large clusters will therefore waste disk space such wasted disk space is called slack space . For cluster sizes which are small versus the average file size, the wasted space per file will be statistically about half of the cluster size for large cluster sizes, the wasted space will become greater. However, a larger cluster size reduces bookkeeping overhead and fragmentation, which may improve Reading computer reading and writing speed overall. Typical cluster sizes range from 1 sector 512 B to 128 sectors 64 Kibibyte KiB . A cluster need not be physically contiguous on the disk it may span more than one track disk drive track or, if Interleaving Interleaving in disk storage sector interleaving is used, may even be discontiguous within a track. This should not be confused with Disk fragmentation fragmentation , as the sectors are still logically contiguous. See also Block data storage External links http www.ntfs.com hard disk basics.htm Sectors 20and 20Clusters Sectors and Clusters Category Computer file systems Category File system management bg cs Cluster pevn disk de Cluster Datentr ger es Cl ster sistema de archivos fr Bloc disque dur id Cluster sistem berkas hu Adat cluster mk nl Cluster bestandssysteem ja ... more details
Many computer systems including DBMSs are used simultaneously by more than one user. This means the computer runs multiple transactions programs at the same time. For example, an airline reservations system is used by hundreds of travel agents and reservation clerks concurrently. Systems in banks, insurance agencies, stock exchanges, and the like are also operated by many users who submit transactions concurrently to the system. If, as is often the case, there is only one CPU, then only one program can be processed at a time. To avoid excessive delays, concurrent systems execute some commands from one program transaction , then suspended that program and execute some commands from the next program, and so on. A program is resumed at the point where it was suspended when it gets its turn to use the CPU again. This is known as interleaving. Uncategorized date March 2011 ... more details
Unreferenced stub auto yes date December 2009 Time Diversity is used in digital communication systems to combat that the transmissions channel may suffer from error burst s due to time varying channel conditions. The error bursts may be caused by fading in combination with a moving receiver, transmitter or obstacle, or by intermittent electromagnetic interference, for example from crosstalk in a cable, or co channel interference from radio transmitters. Time diversity implies that the same data is transmitted multiple times, or a redundant error correcting code is added. By means of bit interleaving, the error bursts may be spread in time. See also Diversity reception schemes DEFAULTSORT Time Diversity Category Radio resource management Wireless stub zh ... more details
Unreferenced stub auto yes date December 2009 There are several ways to organise Memory computers memories with respect to the way they are connected to the cache one word wide memory organisation wide memory organisation interleaved memory organisation independent memory organisation One Word Wide The memory is one Word computer science word wide and connected via a one word wide Computer bus bus to the cache. Wide The memory is more than one word wide usually four words wide and connected by an equally wide bus to the low level cache which is also wide . From the cache multiple busses of one word wide go to a MUX which selects the correct bus to connect to the high level cache. Interleaved There are several memory banks which are one word wide, and one one word wide bus. There is some logic in the memory that selects the correct bank to use when the memory gets accessed by the cache. Memory interleaving is a way to distribute individual addresses over memory modules. Its aim is to keep the most of modules busy as computations proceed. With memory interleaving, the low order k bits of the memory address select a module, and the high order m bits name a location within that module. Hence, consecutive addresses are located in successive modules. A request to access consecutive memory locations can keep several modules busy at the same time. Independent There are several banks, which can all be accessed simultaneously by several buses. DEFAULTSORT Memory Organisation Category Computer memory Memory Geometry Comp sci stub pt Organiza o de mem ria ... more details
OpenAtom is a massively parallel quantum chemistry application written in Charm for simulations on supercomputers. Its developmental version was called LeanCP . Many important problems in material science , chemistry , solid state physics , and biophysics require a modeling approach based on fundamental quantum mechanics quantum mechanical principles. A particular approach that has proved to be relatively efficient and useful is Car Parrinello Molecular Dynamics Car Parrinello ab initio molecular dynamics CPAIMD . It is widely used to study systems consisting of hundreds to thousands of atoms. CPAIMD computations involve a large number of interdependent phases with high communication overhead including multiple concurrent sparse 3D Fast Fourier Transforms 3D FFTs , non square matrix multiplies and few concurrent dense 3D FFTs. Parallelization of this approach beyond a few hundred processors is challenging, due to the complex dependencies among various subcomputations, which lead to complex communication optimization and load balancing problems. Using Charm and its concept of processor virtualization, the phases are discretized into a large number of virtual processors which are, in turn, mapped flexibly onto physical processors, thereby allowing significant interleaving of work. Interleaving is enhanced through both architecturally independent methods and network topology aware mapping techniques. OpenAtom has shown good scaling up to 20,480 processors of IBM s Blue Gene L and 4,096 processors of Cray XT3 . OpenAtom is freely available for download at the OpenAtom http charm.cs.uiuc.edu OpenAtom webpage . Published papers can also be found at the website. See also Charm NAMD List of quantum chemistry and solid state physics software External links http charm.cs.uiuc.edu OpenAtom OpenAtom http charm.cs.uiuc.edu research qmmm LeanCP http charm.cs.uiuc.edu Charm http homepages.nyu.edu mt33 PINY MD PINY.html Piny MD Category Computational chemistry software ... more details
Jinx is a Concurrency computer science concurrency debugger that deterministically controls the interleaving of workloads across processor cores, focusing on shared memory interactions. Using this deterministic approach, Jinx is able to increase the frequency of occurrence of elusive shared memory bugs, sometimes called Unusual software bug Heisenbug Heisenbugs . Jinx works by dynamically building a set of potential interleavings i.e. alternate eventualities, or execution scenarios, that will occur under some future condition that are most likely to result in concurrency faults, and quickly tests those execution paths to surface concurrency problems such as deadlock s, race condition s and atomicity violations that are found in multiprocessing applications. Unlike model checkers, Jinx does not require the specification of a model. Unlike Dynamic program analysis dynamic and Static code analysis static code analysis methods, Jinx is notable in that it produces no false positives spurious bug reports . This is because Jinx actually tests the scenarios that are likely to be bugs, as opposed to just inferring those scenarios by analyzing source code or observing the execution of a program. Jinx is implemented as a hypervisor , giving it the ability to observe the effects of all elements of the software environment on thread interleaving. Jinx operates independently of any programming language or threading libraries or tools. Jinx has been developed by Corensic ref http corensic.com ref in Seattle, Washington based on research performed at the University of Washington ref http sampa.cs.washington.edu sampa Projects Deterministic Shared Memory Multiprocessing .28DMP.29 ref and initially presented at the ASPLOS conference of 2009. Portal Software Testing References reflist Category Debuggers ... more details
Unreferenced date July 2009 In packed pixel or chunky frame buffer organization, the bits defining each pixel are grouped together. For example, if there are 16 bits per pixel, each pixel is represented in two consecutive contiguous 8 bit bytes in the frame buffer a.k.a. screen buffer . If there are 4 bits per pixel 16 colors , each frame buffer byte defines two pixels, one in each nibble . The latter example is as opposed to storing perhaps half of the bits 2 bits for each of four pixels in one byte and the other two bits for each of those four pixels in another byte or bytes. It is also as opposed to interleaving the bits of the two pixels within the byte. As this illustrates, packed pixel organization can be directly contrasted with Planar computer graphics planar organization. See also Highcolor Planar computer graphics Truecolor DEFAULTSORT Packed Pixel Category Computer graphics compu graphics stub ca Chunk es Chunk eo Chunk it Chunk informatica pl Chunky pt Chunk ... more details
Unreferenced date December 2009 Image Radio propagation noise.jpg 300px thumb right Selective fading causes a cloudy pattern to appear on a spectrogram display. Selective fading or frequency selective fading is a radio propagation anomaly caused by partial cancellation of a radio Signalling telecommunication signal by itself &mdash the signal arrives at the receiver by Multipath propagation two different paths , and at least one of the paths is changing lengthening or shortening . This typically happens in the early evening or early morning as the various layers in the ionosphere move, separate, and combine. The two paths can both be skywave or one be groundwave . Selective fading manifests as a slow, cyclic disturbance the cancellation effect, or null , is deepest at one particular frequency, which changes constantly, sweeping through the received Sound audio . The effect can be counteracted by applying some diversity scheme , for example OFDM with subcarrier interleaving and forward error correction , or by using two receiver radio receivers with separate antenna radio antenna s spaced a quarter wavelength apart, or a specially designed diversity reception diversity receiver with two antennas. Such a receiver continuously compares the signals arriving at the two antennas and presents the better signal. See also Attenuation distortion Fading Diversity scheme s OFDM DEFAULTSORT Selective Fading Category Radio frequency propagation fading ko ... more details
Unreferenced stub date December 2009 Otheruses Image E8309 Kosh Kol beach.jpg thumb Mountains of Kyungei Alatoo seen from Koshkol , Kyrgyzstan Alatau or Ala Too Lang kz , Lang ky , Lang ru is a generic name for a number of mountain range s in Central Asia , characterized by interleaving areas of vegetation , scattered rocks and snows. The Alatau Mountains are located in the North East of Kazakhstan Kuznetsk Alatau Mountains in south central Siberia, Russia Several ranges of the Tien Shan Dzungarian Alatau , Kazakhstan China Terskey Alatau , Kyrgyzstan Kungey Alatau Trans Ili Alatau , Kazakhstan Kyrgyzstan Talas Alatau , Kyrgyzstan Kazakhstan Uzbekistan Kyrgyz Alatau , North Tien Shan The name Alatau has been given to Alatau, Kazakhstan , a settlement in Kazakhstan. Ala Too Square , the main square in Bishkek, Kyrgyzstan Alatau Sports Palace Alatau cattle , a breed of cattle from Kazakhstan and Kyrgyzstan . Coord missing Kazakhstan Category Mountain ranges of Kyrgyzstan Category Mountain ranges of Kazakhstan Kazakhstan geo stub Kyrgyzstan geo stub Xinjiang geo stub de Alatau kk nl Alataoe nn Alatau pl A atau uk ... more details
Summary Non free use rationale Article Disk formatting Description Example of obsolete 1987 software program for low level formatting MFM RLL hard drives, to recreate track and sector boundaries, check for media errors, and to also configure the sector interleaving. Source IBM PC XT with 640 kilobytes of memory, text only monochrome video, 360k floppy drive, Western Digital MFM drive controller, and a Seagate 10 megabyte MFM hard drive Portion Low resolution image is 500x455, and was taken with a handheld digital camera of the IBM PC XT monochrome monitor. Slight camera shake so the image is blurry. Purpose Documentation of the obscure low level formatting process that was once common with early IBM PC MFM RLL hard drives, typically under 50 megabytes in total partition size. Replaceability This image generally cannot be replaced by free content. Low level formatting cannot be done with modern IDE SATA drives. This function was typically solely performed by utilities provided by the hard drive or MFM RLL controller manufacturer. Licensing Non free software screenshot ... more details
and Adaptive Coding & Modulation FEC Reed Solomon RS LDPC BCH Interleaving Bit Interleaving Bit Time and Frequency Interleaving Modulation Single Carrier QAM COFDM Pilots Not Applicable Scattered and Continual ... packet. External Interleaving interleaver convolutional interleaving is used to rearrange the transmitted ... more details
Other uses Strip disambiguation In computer data storage , data striping is the technique of segmenting logically sequential data, such as a file, in a way that accesses of sequential segments are made to different physical storage devices. Striping is useful when a processing device requests access to data more quickly than a storage devices can provide access. By performing segment accesses on multiple devices, multiple segments can be accessed concurrently. This provides more data access throughput, which avoids causing the processor to idly wait for data accesses. Striping is used across disk drive s in Redundant array of independent disks RAID storage, network interface s in Grid oriented Storage , and Random access memory RAM in some systems. Method One method of striping is done by interleaving sequential segments on storage devices in a round robin fashion from the beginning of the data sequence. This works well for streaming data, but subsequent random accesses will require knowledge of which device contains the data. If the data is stored such that the physical address of each data segment is assigned a 1 to 1 mapping to a particular device, the device to access each segment requested can be calculated from the address without knowing the offset of the data within the full sequence. Other methods might be employed in which sequential segments are not stored on sequential devices. Such non sequential interleaving can have benefits in some Error detection and correction error correction schemes. Advantages and disadvantages Advantages of striping include performance and throughput. Sequential time interleaving of data accesses allows the lesser data access throughput of each storage devices to be cumulatively multiplied by the number of storage devices employed. Increased throughput allows the data processing device to continue its work without interruption, and thereby finish its procedures more quickly. This is manifested in improved performance of the dat ... more details
, Rapide and Hagner. gallery Image My stamp collection book opened.jpg Stockbook without interleaving between pages Image Stamp stockbook 2545276.JPG Traditional stockbook with glassine interleaving containing ... more details
a modest amount of spectrum, the error correction and time interleaving combine to recover the data ... time based interleaving. Not much exploration has yet taken place into some of the newer or more obscure ... and interleaving processes, it is not possible have quick turnaround conversations. Another problem ... s, with temporal interleaving. This may not be an optimal coding scheme with respect to error correction ... can be eliminated Walsh Turbo 8 bits, a 25 increase in system efficiency The same temporal interleaving techniques could be used with turbo codes, but as a general principle only short length interleaving ... more details
Image with disputed fair use status removed Image IBM logo.svg thumb 128px IBM logo The IBM 7302 Core Storage unit was designed in 1957 1958 for the IBM 7030 Stretch . The IBM 7030 could use from one to sixteen IBM 7302s typically six either individually or in interleaved groups of two or four. The IBM 7090 also used one IBM 7302. The IBM 7094 used one IBM 7302A. The IBM 7094 Model II IBM 7094 II used one IBM 7302, but it was a new model unique to the IBM 7094 II. The IBM 7080 also used one decimal model IBM 7302 with a different core stack than used in the binary models. Binary models of the IBM 7302 1. 16,384 &ndash 72 bit words w 2.18 s cycle time IBM 7302A 2.0 s cycle time The IBM 7030 used this as 16,384 &ndash 64 bit words and an 8 bit ECC. Interleaving of units could reduce effective cycle time to 1.09 s two unit groups or 0.545 s four unit groups . The IBM 7090 used this as 32,768 &ndash 36 bit words. The IBM 7094 used this as 32,768 &ndash 36 bit words. Instructions were fetched in 72 bit word pairs, reducing effective instruction fetch time to 1.0 s. 2. 8,192 &ndash 72 bit words w 2.18 s cycle time The IBM 7030 used this as 8,192 &ndash 64 bit words and an 8 bit ECC. Interleaving of units could reduce effective cycle time to 1.09 s two unit groups or 0.545 s four unit groups . 3. 32,768 &ndash 36 bit words w 1.4 s cycle time and Even Odd word overlapped access. The IBM 7094 II used this as 32,768 &ndash 36 bit words. Because the Even 36 bit word and Odd 36 bit word were independent in this model their accesses could overlap, which could reduce effective cycle time to 0.7 s. Decimal models of the IBM 7302 1. 160,000 &ndash 7 bit characters w 2.18 s cycle time The IBM 7080 used this as 160,000 &ndash 7 bit characters CBA8421 . 2. 80,000 &ndash 7 bit characters w 2.18 s cycle time The IBM 7080 used this as 80,000 &ndash 7 bit characters CBA8421 . The core memory in the IBM 7302 was heated cooled to stabilize its operating characteristics. Early units immersed ... more details
Mergeto Scrambler date February 2010 In telecommunication , a randomizer has the following meanings An algorithm that converts an input string into a seemingly random output string of the same length e.g., by pseudo random ly selecting bits to invert , thus avoiding long sequences of bits of the same value in this context, a randomizer is also referred to as a scrambler . An analog or digital source of unpredictable i.e., high entropy , unbiased, and usually independent i.e., random output bits. A truly random generator may be used to feed a more practical deterministic pseudo random random number generator , which extends the random seed value. note the MIL reference is very unclear on that point does it refer to true randomness, statistical randomness, or cryptographically secure randomness? Scrambling Scramblers are primarily used for two reasons For energy dispersal on the carrier, reducing inter carrier signal interference communication interference . To enable accurate timing recovery on receiver equipment without resorting to redundant line coding. Scramblers are essential components of physical layer system standards besides interleaving interleaved forward error correction coding and modulation . They are usually defined based on linear feedback shift register s LFSRs due to their good statistical properties and ease of implementation in hardware. It is common for physical layer standards bodies to refer to lower layer physical layer and link layer encryption as scrambling as well. ref EN 301 192, Specifications for Data Broadcasting , European Telecommunications Standards Institute ETSI , 2004. ref ref ETR 289, Support for use of scrambling and Conditional Access CA within digital broadcast systems , European Telecommunications Standards Institute ETSI , 1996. ref This may well be because traditional mechanisms employed are based on feedback shift registers as well. Some standards for digital television , such as Conditional access DVB CA and Multiprotocol ... more details
Lucas Fern ndez c. 1474 1542 was a Spain Spanish dramatist and musician , writer in Leonese language . He was born and educated at Salamanca , and was a professor of music there from 1522. Lucas Fern ndez surviving work consists of six plays. Although showing the influence of his rival Juan del Encina , they are notable for their dialogue, humor, and the effective interleaving of song and music with the action of play. The best of the works is an Easter play Auto de la Pasi n , while his Dialogo para cantar is an early example of the zarzuela . Leonesisms Lucas Fern ndez writes with a great influence of Leonese language , ref L pez Morales, 1969 Weissberger, 2003 ref like na feminine for in the , nel masculine for in the , dexay let , diz says , quier wants , sal goes out ... and so many others. Biography Son of Alfonso de Cantalapiedra and Mar a S nchez, he was at the service of the cathedral he defeated his admired Juan del Encina in the oppositions to singer of the Cathedral of Salamanca 1498 to it alluded Encina in his gloga of the great rains. In 1520 he was Abbot of the Church of Santo Tom s in Salamanca. He was professor of music in the University of this city 1522 and appeared in 1533 in the commission of reform of the statutes of the same. See also Leonese language Leonese language writers References references Persondata Metadata see Wikipedia Persondata . NAME Fernandez, Lucas ALTERNATIVE NAMES SHORT DESCRIPTION DATE OF BIRTH PLACE OF BIRTH DATE OF DEATH 1542 PLACE OF DEATH DEFAULTSORT Fernandez, Lucas Category 1470s births Category 1542 deaths Category People from Salamanca Category Leonese language writers Category Spanish dramatists and playwrights es Lucas Fern ndez hu Lucas Fern ndez ... more details
For Interleaving on ADSL lines Fastpath File Shiva Fastpath.JPG thumb right Shiva Fastpath V5 The Kinetics FastPath was an MacIP to TCP IP router created in 1985 to allow Apple Macintosh computers which at the time only had AppleTalk network connections to communicate with other computers on Ethernet networks. The product had five significant revisions known as KFPS 1 through KFPS 5 during its lifetime and was sold by Shiva Networks late in its existence. The FastPath itself was modeled after an implementation of the Stanford Ethernet AppleTalk Gateway SEAGATE created at Stanford University Medical Center by Bill Croft in 1984 and 1985 ref http groups.google.com group net.micro.mac msg f084989e3da699cb?dmode source Bill Croft declares in net.micro.mac that Kinetics are using a modified version of the SEAGATE code ref . SEAGATE was a combination of hardware and software that picked up IP packets from the Ethernet network and encapsulated them inside of DDP packets on the AppleTalk network and conversely picked up specially encoded DDP packets on the AppleTalk network and placed them on the Ethernet network as IP packets. Although a few sites used the actual SEAGATE multibus hardware, it served as a proof of concept and was eclipsed by the Kinetics FastPath and similar hardware gateways by other companies. However, many university and research Fastpath owners continued to run the Stanford gateway software called KIP inside the Kinetics box. This is because KIP was open source and local modifications and adaptations could be made. By 1987, Apple had begun shipping Macintosh computers that were capable of having Ethernet connections directly, but the AppleTalk networking products prospered into the early 1990s, due to the popularity of Apple s plug and play networking. See also Fast path a shorter path through a program than the normal path, using less or faster instructions GatorBox LocalTalk to Ethernet bridge MacIP References references DO NOT ADD THESE INTERWIKI LINKS ... more details
Image Optical Interleaver.gif thumb 400px right Illustration of the function of an optical interleaver and de interleaver An optical interleaver is a 3 port passive fiber optics fiber optic device that is used to combine two sets of dense wavelength division multiplexing DWDM channels odd and even channels into a composite signal stream in an interleaving way. For example, optical interleaver takes two multiplexed signals with 100 GHz spacing and interleaves them, creating a denser DWDM signal with channels spaced 50 GHz apart. The process can be repeated, creating even denser composite signals with 25 GHz or 12.5 GHz spacing. The device can be used in a reverse direction, forming an optical deinterleaver that separates a denser DWDM signal into odd channels and even channels. See schematic diagram. For example, in most DWDM equipment, the standard channel spacing is 100 GHz. But spacing the signal carrying frequencies every 50 or even 25 GHz can double or even quadruple the number of channels per fiber. Thus, optical interleaver can expand the number of channels per fiber, and devices and or networks can be upgraded without requiring that all devices be upgraded. Optical interleaver is based on multiple beam interference . Currently, there are two approaches to building optical interleaver 1 Step phase Michelson interferometer , and 2 birefringence Birefringent crystal networks. The former is based on Michelson interferometer combined with Gires Tournois interferometer . Image Interleaver Spectrum.jpg frame 622px center Transmission spectra of 50 100 GHz optical interleaver at three temperatures See also Optical add drop multiplexer http www.optoplex.com Optical Interleaver.htm Optical Interleaver for fiber optic communications Category Fiber optic communications Interleaver, optical Category Optical devices Interleaver, optical Category Photonics ... more details
Infobox mountain name Mount Joyce photo Joyce2.jpg photo caption North side of Mt Joyce elevation m 1830 elevation ref listing location south side of David Glacier, Antarctica coordinates coord 75 36 S 160 49 E format dms region AQ type mountain display inline,title topo type age first ascent easiest route Mount Joyce is a prominent, dome shaped mountain , 1,830 m, standing 8 miles 13 km northwest of Mount Howard Antarctica Mount Howard in the Prince Albert Mountains , Victoria Land , on the south side of David Glacier . It was first mapped by the British Antarctic Expedition , 1907 09, which named it for Ernest Joyce who was in charge of general stores, dogs, sledges, and zoological collections with the expedition and who had earlier been with the Discovery expedition, 1901 04. Joyce was also with the Ross Sea Party of Shackleton s Imperial Trans Antarctic Expedition , 1914 17. Geology Mount Joyce, along with nearby nunatak s, such as the Trio Nunataks, represent the remnants of a tableland of the Jurassic Ferrar Group, which consists of Kirkpatrick lava s and Ferrar dolerite Sill geology sills , alternating with rafts of sandstone of the Paleozoic and Mesozoic Beacon sandstone Beacon SuperGroup . The Stratum strata dip about 1 2 degrees at most to the west. On Mt Joyce only three major dolerite sills are observed, with two thin interleaving Stratum seams of Beacon sandstone Beacon sediments ref name Worner cite journal last Worner first G. year 1992 title Kirkpatrick Lavas, Exposure Hill Formation and Ferrar Sills in the Prince Albert Mountains, Victoria Land, Antarctica journal Polarforschung volume 60 pages 97 90 ref References reflist usgs gazetteer DEFAULTSORT Joyce Category Prince Albert Mountains Category Mountains of Victoria Land ... more details
In mathematics and computer science , trace theory aims to provide a concrete mathematical underpinning for the study of concurrent computation and process calculi . The underpining is provided by an algebraic definition of the free partially commutative monoid or trace monoid , or equivalently, the history monoid , which provides a concrete algebraic foundation, analogous to the way that the free monoid provides the underpining for formal language s. The power of trace theory stems from the fact that the algebra of dependency graph s such as Petri net s is isomorphic to that of trace monoids, and thus, one can apply both algebraic formal language tools, as well as tools from graph theory . While the trace monoid had been studied by Pierre Cartier mathematician Pierre Cartier and Dominique Foata for its combinatorics in the 1960s, trace theory was first formulated by Antoni Mazurkiewicz in the 1970s, in an attempt to evade some of the problems in the theory of concurrent computation, including the problems of interleaving and non deterministic choice with regards to refinement in process calculi. References V. Diekert, G. Rozenberg, eds. The Book of Traces , 1995 World Scientific, Singapore ISBN 9810220588 Volker Diekert, Yves Metivier, http citeseer.ist.psu.edu diekert97partial.html Partial Commutation and Traces , In G. Rozenberg and Arto Salomaa A. Salomaa , editors, Handbook of Formal Languages , Vol. 3 , Beyond Words . Springer Verlag, Berlin, 1997. Volker Diekert, Combinatorics on traces , LNCS 454, Springer, 1990, ISBN 3540530312 Category Concurrent computing Category Formal languages formalmethods stub ... more details
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