Day 274~366

The electric telephone was invented in the 1870s, it was based on earlier work with harmonic (multi-signal) telegraphs. The first commercial telephone services were set up in 1878 and 1879 on both sides of the Atlantic in the cities of New Haven and London. Alexander Graham Bell held the master patent for the telephone that was needed for such services in both countries. All other patents for electric telephone devices and features flowed from this master patent. Credit for the invention of the electric telephone has been frequently disputed, and new controversies over the issue have arisen from time-to-time. As with other great inventions such as radio, television, the light bulb, and the digital computer, there were several inventors who did pioneering experimental work on voice transmission over a wire, who then improved on each other’s ideas. However, the key innovators were Alexander Graham Bell and Gardiner Greene Hubbard, who created the first telephone company, the Bell Telephone Company in the United States, which later evolved into American Telephone & Telegraph (AT&T), at times the world’s largest phone company.
The first commercial telephone services were set up in 1878 and 1879 on both sides of the Atlantic in the cities of New Haven, Connecticut, and London, England. The technology grew quickly from this point, with inter-city lines being built and telephone exchanges in every major city of the United States by the mid-1880s. The First transcontinental telephone call occurred on January 25, 1915. Despite this, transatlantic voice communication remained impossible for customers until January 7, 1927 when a connection was established using radio. However no cable connection existed until TAT-1 was inaugurated on September 25, 1956 providing 36 telephone circuits.
In 1880, Bell and co-inventor Charles Sumner Tainter conducted the world’s first wireless telephone call via modulated lightbeams projected by photophones. The scientific principles of their invention would not be utilized for several decades, when they were first deployed in military and fiber-optic communications.
The first transatlantic telephone cable (which incorporated hundreds of electronic amplifiers) was not operational until 1956, only six years before the first commercial telecommunications satellite, Telstar, was launched into space.


Day 273~366

Revolutions per minute (abbreviated rpm, RPM, rev/min, r/min) is a measure of the frequency of rotation, specifically the number of rotations around a fixed axis in one minute. It is used as a measure of rotational speed of a mechanical component. In the French language, tr/mn (tours par minute) is the common abbreviation. The German language uses the abbreviation U/min or u/min (Umdrehungen pro Minute).
A gramophone record (phonograph record in American English) or vinyl record, commonly known as a record, is an analogue sound storage medium in the form of a flat polyvinyl chloride(previously shellac) disc with an inscribed, modulated spiral groove. The groove usually starts near the periphery and ends near the center of the disc. Phonograph records are generally described by their diameter in inches (12″, 10″, 7″), the rotational speed in rpm at which they are played (16 2⁄3, 33 1⁄3, 45, 78), and their time capacity, determined by their diameter and speed (LP [long playing], 12-inch disc, 33 1⁄3 rpm; SP [single], 10-inch disc, 78 rpm, or 7-inch disc, 45 rpm; EP [extended play], 12-inch disc, 33 1⁄3 or 45 rpm); their reproductive quality, or level of fidelity(high-fidelity, orthophonic, full-range, etc.); and the number of audio channels (mono, stereo,quad, etc.).

The long playing (nicknamed the LP; in full a 33 1⁄3 rpm microgroove) record is a vinyl record format, an analog sound storage medium. Introduced by Columbia in 1948, it was soon adopted as a new standard by the entire record industry. Apart from relatively minor refinements and the important later addition of stereophonic sound, it has remained the standard format for vinyl albums. At the time the LP was introduced, nearly all phonograph records for home use were made of an abrasive (and therefore noisy) shellac compound, employed a much larger groove, and played at approximately 78 revolutions per minute (rpm), limiting the playing time of a 12-inch diameter record to less than five minutes per side. The new product was a 12- or 10-inch (30 or 25 cm) fine-grooved disc made of vinyl and played with a smaller-tipped “microgroove” stylus at a speed of 33 1⁄3 rpm. Each side of a 12-inch LP could play for more than 20 minutes. Only the microgroove standard was new, as both vinyl and the 33 1⁄3 rpm speed had been used for special purposes for many years, as well as in one unsuccessful earlier attempt to introduce a long-playing record for home use by RCA Victor.
Although the LP was suited to classical music because of its extended continuous playing time, it also allowed a collection of ten or more pop music recordings to be put on a single disc. Previously, such collections, as well as longer classical music broken up into several parts, had been sold as sets of 78 rpm records in a specially imprinted “record album” consisting of individual record sleeves bound together in book form. The use of the word “album” persisted for the one-disc LP equivalent.

The phonograph disc record was the primary medium used for music reproduction until late in the 20th century, replacing the phonograph cylinder record—with which it had co-existed from the late 1880s through to the 1920s—by the late 1920s. Records retained the largest market share even when new formats such as compact cassette were mass-marketed. By the late 1980s, digital media, in the form of the compact disc, had gained a larger market share, and the vinyl record left the mainstream in 1991. From the 1990s to the 2010s, records continued to be manufactured and sold on a much smaller scale, and were especially used by disc jockeys (DJ)s, released by artists in some genres, and listened to by a niche market of audiophiles. The phonograph record has made a niche resurgence in the early 21st century – 9.2 million records were sold in the U.S. in 2014, a 260% increase since 2009. Likewise, in the UK sales have increased five-fold from 2009 to 2014.


Day 272~366

A fluid ounce is a unit of volume typically used for measuring liquids. It is equivalent to approximately 30 millilitres. Whilst various definitions have been used throughout history, two remain in common use: the imperial and the United States customary fluid ounce. An imperial fluid ounce is 1⁄20 of an imperial pint, 1⁄160 of an imperial gallon or approximately 28.4 ml. A US fluid ounce is 1⁄16 of a US fluid pint, 1⁄128 of a US liquid gallon or approximately 29.6 ml. The fluid ounce is distinct from the ounce, a unit of weight or mass, although they do have a historical relationship, and it is sometimes referred to simply as an “ounce” where context makes the meaning clear.
The fluid ounce was originally the volume occupied by one ounce of some substance, such as wine (in England) or water (in Scotland). The ounce in question varied depending on the system of fluid measure, such as that used for wine versus ale. Various ounces were used over the centuries, including the Tower ounce, troy ounce, avoirdupois ounce, and various ounces used in international trade, such as Paris troy.
In 1824, the British Parliament defined the imperial gallon as the volume of ten pounds of water. The gallon was divided into four quarts, the quart into two pints, the pint into four gills and the gill into five ounces. Thus, there were 160 imperial fluid ounces to the gallon making the mass of a fluid ounce of water approximately one avoirdupois ounce (28.4 g). This relationship is still approximately valid even though the imperial gallon’s definition was later revised to be 4.54609 litres, making the imperial fluid ounce exactly 28.4130625 ml.
The US fluid ounce is based on the US gallon, which is based on the wine gallon of 231 cubic inches that was used in England prior to 1824. With the adoption of the international inch, the US fluid ounce became 29.5735295625 ml exactly, or about 4% larger than the imperial unit.
A litre (liter in the United States) is one of the metric units of volume. It is not an SI unit.
The metric system was first introduced in France in 1791. That system did not have its own unit of capacity or volume because volume can be measured in cubic metres. In 1793 work to make the metric system compulsory in France was started by the Temporary Commission of Republican Weights and Measures. Due to public demand, the commission said that the cubic metre was too big for everyday use. They said that a new unit based on the old cadil should be used instead. One cadil was to be 0.001 cubic metres. This was equivalent to a cube with sides 10 cm. The cadil was also known as the pinte or the litron. The pinte had been an old French unit of measure of capacity. In 1795 the definition was revised. The cadil was given the name litre.

One litre is the volume of one cubic decimetre, that is a cube of 10 x 10 x 10 centimetres. One litre of water has the mass of exactly one kilogram. This results from the definition given in 1795, where the gram was defined as the weight of one cubic centimetre of melting ice.
The symbol for litre is “L” or “l”.
For smaller volumes the decilitre is used: 10 dl = one litre.
For smaller volumes the centilitre is used: 100 cl = one litre.
For smaller volumes the millilitre is used: 1000 ml = one litre.
The capital letter “L” is preferred by some people as the small “l” can look like the number one “1”.
Most British people still use imperial units in everyday life for volume in some cases, especially pints of milk, beer, and rational fractions thereof, but rarely for canned or bottled soft drinks or petrol. Fuel consumption for vehicles is often discussed in miles per gallon, though official figures always include litres per 100 km equivalents. When sold “draught” in licensed premises, beer and cider must be measured out and sold in pints and half-pints. Cow’s milk is available in both litre- and pint-based containers in supermarkets and shops.



Day 271~366

Prior to the introduction of number plates there was the Locomotive and Highways Act 1896, which contributed to the rise in popularity for motor vehicles. The Act increased the speed limit and introduced compulsory lights for safety, but more relevantly it required vehicles to be registered by the local council. Even such ideas like driving on the left side of the road was introduced in the Act. After the turn of the century the number of vehicles on the road reached 5,000. While today this seems a low figure it was quite scary at the time. The Motor Car Act 1903 was introduced as a result. The Act was intended to help identify vehicles and their drivers, and it did this by mandating the display of registration marks in a prominent position.
The first registration marks were made up of one letter and one number. The first, A1, was issued by London County Council in 1903. This style continued until all possible combinations ran out. At this point the format changed to two letters and up to four numbers.
Besides a 1909 Act which introduced road tax to fund road improvements, the Roads Act 1920 was the biggest change in quite some time. This new act changed the registration process so that Councils had to register all vehicles at the time of licensing, assigning a separate number to each vehicle. Different councils were allowed different characters for their licensing. For example, number plates starting KA were exclusive to Liverpool.
The problem with this way or registration is that more populous areas ran out of possible marks quicker than other areas. In the case of Liverpool the KA series ran out by 1927, but the SJ series issued by Bute Council lasted until 1963. Areas that did run out of plates though received new formats – three letters and three numbers – and later a reversed format (three numbers and three letters). Even these would run out though; something needed to be done. In 1963 a new format was introduced, known as suffix registration marks. These displayed three letters, up to three numbers, and then the letter A. This meant any vehicle registered in 1963 would have an A on the end. The following year the last letter was changed to a B, so any vehicle registered in 1964 would end in a B. This pattern continued until 1983 when the format was reversed (the prefix format) and the first letter became the year of registration. In September 2001, the current format number plate was introduced, made up of three parts:
1)Local memory tag The first two letters show where the vehicle was registered. The first represents the region and the second a DVLA local office.
2)Age identifier The two numbers in the middle show the age of the vehicle down to a six month period – March to August or September to February. The age identifier changes on 1 March and 1 September.
3)Random letters The last three letters are random and give the car a unique identity.
Under rules introduced in April 2009, drivers in England, Scotland and Wales can display the Union flag, Cross of St George, Saltire or Red Dragon of Wales.
No other symbols or flags can be displayed on number plates.

(info from National Numbers, and The AA)

This is really boring in comparison to the USA.day271-copy

One from my time in USA, much cooler than ours.


Day 270~377

An ISBN is an International Standard Book Number. ISBNs were 10 digits in length up to the end of December 2006, but since 1 January 2007 they now always consist of 13 digits. ISBNs are calculated using a specific mathematical formula and include a check digit to validate the number.
Each ISBN consists of 5 elements with each section being separated by spaces or hyphens. Three of the five elements may be of varying length:
• Prefix element – currently this can only be either 978 or 979. It is always 3 digits in length
• Registration group element – this identifies the particular country, geographical region, or language area participating in the ISBN system. This element may be between 1 and 5 digits in length
• Registrant element – this identifies the particular publisher or imprint. This may be up to 7 digits in length
• Publication element – this identifies the particular edition and format of a specific title. This may be up to 6 digits in length
• Check digit – this is always the final single digit that mathematically validates the rest of the number. It is calculated using a Modulus 10 system with alternate weights of 1 and 3.
What is an ISBN used for?
An ISBN is essentially a product identifier used by publishers, booksellers, libraries, internet retailers and other supply chain participants for ordering, listing, sales records and stock control purposes. The ISBN identifies the registrant as well as the specific title, edition and format.
What does an ISBN identify?
ISBNs are assigned to text-based monographic publications (i.e. one-off publications rather than journals, newspapers, or other types of serials).
Any book made publicly available, whether for sale or on a gratis basis, can be identified by ISBN.
In addition, individual sections (such as chapters) of books or issues or articles from journals, periodicals or serials that are made available separately may also use the ISBN as an identifier.
With regard to the various media available, it is of no importance in what form the content is documented and distributed; however, each different product form (e.g. paperback, EPUB, .pdf) should be identified separately.
(info from www.isbn-international.or)


Day 268~366

Hymns Ancient and Modern is a hymnal in common use within the Church of England and resulted out of the efforts of the Oxford Movement. Over the years it has grown into a large family of hymnals. As such, the Hymns Ancient and Modern set the standard for the current hymnal in the Church of England. The Oxford Movement, an ecclesiastical reform movement within the Anglican Church, wanted to recover the lost treasures of Breviaries and Service Books of the ancient Greek and Latin churches. As a result Greek, Latin and even German hymns in translation entered the mainstream of English hymnody. Besides stimulating the translation of medieval hymns, and use of plainsong melodies, the Oxford Reformers, also began to write original hymns. The growing popularity of hymns inspired the publication of more than 100 hymnals during the period 1810 – 1850. The sheer number of these collections prevented any one of them from being successful. The Hymns Ancient and Modern was a rather eclectic collection of hymns that blended a broad series of hymns from different religious traditions in order to achieve a standard edition. It experienced immediate and overwhelming success, becoming possibly the most popular English hymnal ever published. The music, expressive and tuneful, greatly assisted to its popularity.Total sales in 150 years were over 170 million copies.


Day 267~366

The tarot (first known as trionfi and later as tarocchi, tarock, and others) is a pack of playing cards (most commonly numbering 78), used from the mid-15th century in various parts of Europe to play a group of card games such as Italian tarocchini and French tarot. From the late 18th century until the present time the tarot has also found use by mystics and occultists for divination. Tarot cards are used throughout much of Europe to play card games.
In English-speaking countries, where these games are largely unplayed, tarot cards are now used primarily for divinatory purposes. Occultists call the trump cards and the Fool “the major arcana” while the ten pip and four court cards in each suit are called minor arcana. (Pips are small but easily countable items. The term is used to describe the dots on dominoes and dice, the symbols that denote suits and value of playing cards). The cards are traced by some occult writers to ancient Egypt or the Kabbalah but there is no documented evidence of such origins or of the usage of tarot for divination before the 18th century.

The Major Arcana (greater secrets), or trump cards, consists of 22 cards without suits: The Magician, The High Priestess, The Empress, The Emperor, The Hierophant, The Lovers, The Chariot, Strength, The Hermit, Wheel of Fortune, Justice, The Hanged Man, Death, Temperance, The Devil, The Tower, The Star, The Moon, The Sun, Judgement, The World and The Fool. Cards from The Magician to The World are numbered in Roman numerals from I to XXI, while The Fool is the only unnumbered card, sometimes placed at the beginning of the deck as 0, or at the end as XXII.
The Minor Arcana (lesser secrets) consists of 56 cards, divided into four suits of 14 cards each; ten numbered cards and four court cards. The court cards are the King, Queen, Knight and Page/Jack, in each of the four tarot suits. The traditional Italian tarot suits are swords, batons/wands, coins and cups; in modern tarot decks, however, the batons suit is often called wands, rods or staves, while the coins suit is often called pentacles or disks.

The Rider-Waite tarot deck (originally published 1910) is one of the most popular tarot decks in use today in the English-speaking world.[1] Other suggested names for this deck include the Rider-Waite-Smith, Waite-Smith, Waite-Colman Smith or simply the Rider deck. The cards were drawn byillustrator Pamela Colman Smith from the instructions of academic and mystic A. E. Waite, and published by the Rider Company.
The variety of decks in use is almost endless, and grows yearly. For instance, cat-lovers may have the Tarot of the Cat People, a deck replete with cats in every picture. The Tarot of the Witches and the Aquarian Tarot retain the conventional cards with varying designs. The Tree of Life Tarot’s cards are stark symbolic catalogs; and The Alchemical Tarot, created by Robert M. Place, combines traditional alchemical symbols with tarot images.
These contemporary divination decks change the cards to varying degrees. For example, the Motherpeace Tarot is notable for its circular cards and feminist angle where the male characters have been replaced by females. The Tarot of Baseball has suits of bats, mitts, balls, and bases; “coaches” and “MVPs” instead of Queens and Kings; and major arcana cards such as “The Catcher”, “The Rule Book”, and “Batting a Thousand”. In the Silicon Valley Tarot, major arcana cards include The Hacker, Flame War, The Layoff and The Garage; the suits are Networks, Cubicles, Disks and Hosts; the court cards CEO, Salesman, Marketeer and New Hire.
The Eclectic Tarot, which you see here, is a 78-card Austrian deck, published in 1986.
Josef Machynka used an eclectic mix of tarot traditions for inspiration, and his major arcana have detailed and vivid scenes, while the minors have suit elements arranged in geometric patterns .


Day 266~366

100 days left now 🙂

Quinquereme is (apparently) an absorbing nautical dice game of strategy and chance,of Ancient Rome. The instructions are quite mind boggling, so I will spare you the details, but basically each player has 3 throws of the dice at each turn, and keep some dice back each time to try and complete a category. The categories are all named after roman ships and whoever has the highest score at the end of 12 turns, wins. Although the game in it’s original format has disappeared from current play, many variations exist throughout the world, probably as a result of the popularity of this game on merchant ships throughout the ages.

From the 4th century BC on, new types of oared warships appeared in the Mediterranean Sea, superseding the trireme and transforming naval warfare. Ships became increasingly larger and heavier, including some of the largest wooden ships ever constructed. These developments were spearheaded in the Hellenistic Near East, but also to a large extent shared by the naval powers of the Western Mediterranean, more specifically Carthage and the Roman Republic. Perhaps the most famous of the Hellenistic-era warships, because of its extensive use by the Carthaginians and Romans, the quinquereme was invented by the tyrant of Syracuse Dionysius I (r. 405–367 BC) in 399 BC as part of a major naval armament programme directed against the Carthaginians. During most of the 4th century, the “fives” were the heaviest type of warship, and often used as flagships of fleets composed of triremes and quadriremes Sidon had them by 351, and Athens fielded some in 324. According to Polybius, at the Battle of Ecnomus the Roman quinqueremes carried a total crew of 420, 300 of whom were rowers, and the rest marines. Leaving aside a deck crew of ca. 20 men, and accepting the 2–2–1 pattern of oarsmen, the quinquereme would have 90 oars in each side, and 30-strong files of oarsmen. The fully decked quinquereme could also carry a marine detachment of 70 to 120, giving a total complement of about 400.[13] A “five” would be ca. 45 m long, displace around 100 tonnes, be some 5 m wide at water level, and have its deck standing ca. 3 m above the sea. Polybius is explicit in calling the quinquereme superior as a warship to the old trireme, which was retained in service in significant numbers by many smaller navies. Accounts by Livy and Diodorus Siculus also show that the “five”, being heavier, performed better than the triremes in bad weather.


Day 263~366

An audiogram is a graph that shows the audible threshold for standardized frequencies as measured by an audiometer. The Y axis represents intensity measured in decibels and the X axis represents frequency measured in Hertz.The threshold of hearing is plotted relative to a standardised curve that represents ‘normal’ hearing, in dB(HL).
Audiograms are set out with frequency in hertz (Hz) on the horizontal axis, most commonly on a logarithmic scale, and a linear dBHL scale on the vertical axis.
For humans, normal hearing is between −10 dB(HL) and 20 dB(HL), although 0 dB from 250 Hz to 8 kHz is deemed to be ‘average’ normal hearing. Audiograms are produced using a piece of test equipment called an audiometer, and this allows different frequencies to be presented to the subject, usually over calibrated headphones, at any specified level. Most commonly, “conventional” audiometry (utilising audiograms up to 8 kHz) is used to measure hearing status. Ideally the audiogram would show a straight line, but in practice everyone is slightly different, and small variations are considered normal. Larger variations, especially below the norm, may indicate hearing impairment which occurs to some extent with increasing age, but may be exacerbated by prolonged exposure to fairly high noise levels such as by living close to an airport or busy road, work related exposure to high noise, or brief exposure to very high sound levels such as gunshot or music in either a loud band or clubs and pubs. Hearing impairment may also be the result of certain diseases such as CMV or Ménière’s disease and these can be diagnosed from the shape of the audiogram.


Day 262~366

If you need an illustration of the accelerating speed of technological change, look no further than the electronic calculator, that modest little device that does the most complex sum instantly and that you hold in the palm of your hand.
Or more likely don’t any more… for the pocket calculator, which took more than four millennia to evolve and only reached its current form in the 1990s, is already obsolescent, if not actually obsolete.

It had taken 3,700 years to move from the abacus to the first mechanical calculators and a further 250 years for mechanics to give way to electronics. Yet it would take barely a decade for the calculator to make its third metamorphosis, from a heavy, bulky, expensive desktop machine that needed AC mains power to a cheap and compact battery or solar-powered device that would slip into a pocket or wallet.
To make that transition, engineers had to solve three huge principal challenges: replacing boards of transistors with integrated microchips, designing less power-hungry electronics and displays that could run on batteries and developing slimmer, simpler control mechanisms.
Texas Instruments prototype ‘Cal-Tech’ prototype of 1967 with its compact form was a prophet of the future, but it still used transistors and needed mains power.
However, within the next thee years, calculator development became the leading edge of Large Scale Integration (LSI) semiconductor development, with strategic alliances formed between the mostly Japanese calculator manufacturers and the largely U.S. semiconductor companies. Thus Canon teamed with Texas Instruments, Hayakawa Electric (Sharp Corporation) with North-American Rockwell, Busicom with Mostek and Intel, and General Instrument with Sanyo.
By 1969, a calculator could be made using just a few low power consumption chips, allowing the size and power consumption to be drastically reduced. Yet even as they were introduced, these calculators were already obsolete as well as being too expensive for most consumers.
Within a year, Sinclair had produced the Cambridge as the first low-cost calculator, priced at £29.95 (or £24.95 in kit form). The Sinclair calculators cost far less than the competition, but had an ugly bulge in the back for the PP9v battery and with a design that frequently led to errors when doing compound sums. Hewlett Packard and Texas followed suit with machines capable of complex mathematics. During the ‘Calculator Wars’ of the mid-1970s, most of the specialist and ‘me, too’ manufacturers disappeared, leaving a market dominated by five major brands: Sharp, Texas, HP, Canon and the new kid on the block, Casio. The end result, by 1978, was a new generation of pocket calculators with power consumption so low that they could be driven by solar cells. By 1980, pocket and desktop calculators had essentially reached the forms we recognise today; compact in form, using single chips and LCD displays, operated via silicone membrane or dome switch keyboards, powered by solar cells or button batteries and capable of a wide range of functions. Pocket calculators had also become very cheap, with some selling for as little as $1.99. Before long, companies were starting to give pocket calculators away as freebies, much as USB memory sticks are today.
As the 80s gave way to the 1990s, new threats emerged to the calculator, the smart phone and PDA’s. Four main factors are keeping the calculator alive. One is that designs have been successively optimised to purpose, producing a level of function and capability that even tailored apps struggle to emulate. The second is the high price of current smartphones and tablets while the third is that some people just find it easier, quicker and more precise to operate a physical device than a touchscreen.
Last, and arguably most important, ‘dumb’ calculators have over the decades earned a place in school and university exam rooms that remains closed off to ‘smart‘ tablets and phones for the foreseeable future.

The full history of calculators is really quite phenomenal and surprisingly interesting,and this site is where I got the information from :-  


This one is my old and trusted basic add’emup and I still like it better than the smart phone app. 🙂

Day 261~366

Many public bus services are run to a specific timetable giving specific times of departure and arrival at waypoints along the route. These are often difficult to maintain in the event of traffic congestion, breakdowns, on/off bus incidents, road blockages or bad weather. Predictable effects such as morning and evening rush hour traffic are often accounted for in timetables using past experience of the effects, although this then prevents the opportunity for drafting a ‘clock face’ timetable where the time of a bus is predictable at any time through the day. Predictable short term increases in passenger numbers may be dealt with by providing “duplicate” buses, where two or more buses operate the same slot in the timetable. Unpredictable problems resulting in delays and gaps in the timetabled service may be dealt with by ‘turning’ a bus early before it reaches it terminus, so that it can fill a gap in the opposite direction, meaning any passengers on the turned bus need to disembark and continue on a following bus. Also, depending on the location of the bus depot, replacement buses may be dispatched from the depot to fill in other gaps, starting the timetable part way along the route.
There is a common cliché that people “wait all day, and then three come along at once”, in relation to a phenomenon where evenly timetabled bus services can develop a gap in service followed by buses turning up almost simultaneously. This occurs when the rush hour begins and numbers of passengers at a stop increases, increasing the loading time, and thus delay scheduled service. The following bus then catches up because it begins to be delayed less at stops due to fewer passengers waiting. This is called bus bunching. This is prevented in some cities such as Berlin by assigning every stop arrival times where scheduled buses should arrive no earlier than specified.
Some services may have no specific departure times, the timetable giving the frequency of service on a route at particular phases of the day. This may be specified with departure times, but the over-riding factor is ensuring the regularity of buses arriving at stops. These are often the more frequent services, up to the busiest bus rapid transit schemes. For headway-based schemes, problems can be managed by changing speed, delaying at stops and leap-frogging a bus boarding at a stop.
Services may be strictly regulated in terms of level of adherence to timetables, and how often timetables may be changed. Operators and authorities may employ on street bus inspectors to monitor adherence in real time. Service operators often have a control room, or in the case of large operations, route controllers, who can monitor the level of service on routes and can take remedial action if problems occur. This was made easier with the technological advances of two way radio contact with drivers, and vehicle tracking systems.

(info from wiki)


Day 260~366

A clock is an instrument to indicate, keep, and co-ordinate time. The word clock is derived ultimately (via Dutch, Northern French, and Medieval Latin) from the Celtic words clagan and clocca meaning “bell”. A silent instrument missing such a striking mechanism has traditionally been known as a timepiece.In general usage today a “clock” refers to any device for measuring and displaying the time. Watches and other timepieces that can be carried on one’s person are often distinguished from clocks. The clock is one of the oldest human inventions, meeting the need to consistently measure intervals of time shorter than the natural units: the day, the lunar month, and the year. Devices operating on several physical processes have been used over the millennia. A sundial shows the time by displaying the position of a shadow on a flat surface. There are a range of duration timers, a well-known example being the hourglass. Water clocks, along with the sundials, are possibly the oldest time-measuring instruments. A major advance occurred with the invention of the verge escapement, which made possible the first mechanical clocks around 1300 in Europe, which kept time with oscillating timekeepers like balance wheels. Spring-driven clocks appeared during the 15th century. During the 15th and 16th centuries, clockmaking flourished. The next development in accuracy occurred after 1656 with the invention of the pendulum clock. A major stimulus to improving the accuracy and reliability of clocks was the importance of precise time-keeping for navigation. The electric clock was patented in 1840. The development of electronics in the 20th century led to clocks with no clockwork parts at all.
The timekeeping element in every modern clock is a harmonic oscillator, a physical object (resonator) that vibrates or oscillates repetitively at a precisely constant frequency. This object can be a pendulum, a tuning fork, a quartz crystal, or the vibration of electrons in atoms as they emit microwaves. Analog clocks usually indicate time using angles. Digital clocks display a numeric representation of time. Two numeric display formats are commonly used on digital clocks: 24-hour notation and 12-hour notation. Most digital clocks use electronic mechanisms and LCD, LED, or VFD displays. For convenience, distance, telephony or blindness, auditory clocks present the time as sounds. There are also clocks for the blind that have displays that can be read by using the sense of touch. Some of these are similar to normal analog displays, but are constructed so the hands can be felt without damaging them. The evolution of the technology of clocks continues today.
The study of timekeeping is known as horology.

(info from wiki)