閱讀追求知識，當然得明白知識是什麼︰

什麼是『知識』？長久以來，西方的主流思潮中有一個稱之為『JTB』 justified true belief  的『經確證的真信念』之理論，它是這麼定義『知識』與『知道』的︰

在 這個定義下『知道□』意味著有『□的知識』，因為『知識』是由『真的命題』構成，所以必須有第一條件；如果某甲 『聽說』過 □ ，但是不相信，或者以為它是『假的』，當然不能說他知道□；再者雖說某甲相信□，卻出於無『理據』，比方說從『不知哪裡』得來的，一但『爭論』將無法『辯 護其說』，所以也不能講他真知道□。如此說來，這個定義該是很完善的了，但是卻受到美國哲學家 Edmund Gettier 的反駁，他說即使上述的三條要件都得到了滿足，有些情況下我們仍然不能聲稱『某甲知道□』── 這就是知名的『葛梯爾問題』 ──。如今葛梯爾問題之多都成『問題集』了，於此就說一個經典的『空地上的奶牛』 The Cow in the field 問題︰

一 位農民正擔心自己獲獎的奶牛走失了；這時送奶工到了農場，告訴他說︰不必擔心，他看到那頭奶牛在附近的一塊空地上。雖然農民很相信送奶工，但是他還是親自 的望了望，見著了熟悉的黑白相間之物，感覺滿意的放下心來。隔了一會兒，送奶工走過那塊空地想再次確認，他發現那頭奶牛確實是在那裡，不過現在它躲進樹林 裡了，並且空地上還有著一大張黑白相間的紙纏在樹上。顯然是，農民把這張紙錯認成那頭奶牛的了；於是問題就來了，雖然奶牛一直都在空地上，假使農民說自己 知道奶牛在空地上時，此時這句話是正確的嗎？

現今人類的所有知識中，大概物理學能算是『最嚴謹』的科學之一的吧！然而它一路走來爭議卻也是不斷，至今仍然持續著，這又是為什麼呢？就像『天下烏鴉一般黑』這句話，就算它能符合 JTB 的知識理論，假使有人說︰萬一有隻白烏鴉呢？另一人辯︰在大自然裡，這是不可能的事？於是這人又說︰『藍玫瑰』人都造的出了，造出『白烏鴉』只是早晚的事。與葛梯爾問題相較，『基因改寫』的爭議之大，可謂『大烏比小烏』的了。

─── 摘自《基因改寫 ── Thue 改寫系統之補充《二》》

 

創造事物利用厚生，需謹慎周全倫常義理︰

─── 摘自《知未知‧既未濟》

 

或許能悠遊天地時物，領會自然人生之旨乎？？

《黃帝陰符經》又稱《陰符經》，全書一卷三篇，傳聞是黃帝所撰，學者大多認為是後人偽托，現有三說：戰國時的蘇秦，北魏的寇謙之，或唐朝的李荃。這部經即使在中國古代的哲學和兵法中都有一定的地位。《陰符經》更是道教的一部重要道經，歷代對它的註解僅次於《道德經》和《南華真經》。《陰符經》有多種版本，在此僅舉一本，略探其自然人生之旨。

《黃帝陰符經》

觀天之道，執天之行，盡矣。天有五賊，見之者昌。五賊在心，施行於天，宇宙在乎手，萬物生乎身。天性，人也；人性，機也 ；立天之道以定人也。天發殺機，斗轉星移；地發殺機，龍蛇起陸 ；人發殺機，天地反覆；天人合德，萬變定基。性有巧拙，可以伏藏。九竅之邪，在乎三要。可以動靜。火生於木，禍發必克，奸生於國，時動必潰；知之修練，謂之聖人。

天生天殺，道之理也。天地萬物之盜；萬物人之盜；人萬物之盜也。三盜既宜，三才既安。故曰：食其時，百骸治；動其機，萬化安。人知其神而神，不知不神而所以神。日月有數，大小有定 ，聖功生焉，神明出焉。其盜機也，天下莫能見，莫能知也。君子得之固躬，小人得之輕命。

瞽者善聽，聾者善視。絕利一源，用師十倍；三反晝夜，用師萬倍。心生於物，死於物，機在於目。天之無恩而大恩生，迅雷烈風，莫不蠢然。至樂性餘，至靜性廉。天之至私，用之至公。擒之制在氣。生者死之根，死者生之根。恩生於害，害生於恩。愚人以天地文理聖，我以時物文理哲。人以愚虞聖，我以不愚虞聖。人以奇期聖，我以不奇期聖。沈水入火，自取滅亡。自然之道靜 ，故天地萬物生。天地之道浸，故陰陽勝。陰陽相推，而變化順矣。是故聖人知自然之道不可違，因而制之至靜之道，律曆所不能契。爰有奇器，是生萬象，八卦甲子，神機鬼藏。陰陽相勝之術，昭昭乎盡乎象矣。

─── 摘自《天地文理聖,時物文理哲？！》

 

也可曉科技亦是時物也！！

Autofocus

An autofocus (or AF) optical system uses a sensor, a control system and a motor to focus on an automatically or manually selected point or area. An electronic rangefinder has a display instead of the motor; the adjustment of the optical system has to be done manually until indication. Autofocus methods are distinguished by their type as being either active, passive or hybrid variants.

General

Autofocus systems rely on one or more sensors to determine correct focus. Some AF systems rely on a single sensor, while others use an array of sensors. Most modern SLR cameras use through-the-lens optical AF sensors, with a separate sensor array providing light metering, although the latter can be programmed to prioritize its metering to the same area as one or more of the AF sensors.

Through-the-lens optical autofocusing is now often speedier and more precise than can be achieved manually with an ordinary viewfinder, although more precise manual focus can be achieved with special accessories such as focusing magnifiers. Autofocus accuracy within 1/3 of the depth of field (DOF) at the widest aperture of the lens is common in professional AF SLR cameras.

Most multi-sensor AF cameras allow manual selection of the active sensor, and many offer automatic selection of the sensor using algorithms which attempt to discern the location of the subject. Some AF cameras are able to detect whether the subject is moving towards or away from the camera, including speed and acceleration data, and keep focus on the subject — a function used mainly in sports and other action photography; on Canon cameras this is known as AI servo, while on Nikon cameras it is known as “continuous focus”.

The data collected from AF sensors is used to control an electromechanical system that adjusts the focus of the optical system. A variation of autofocus is an electronic rangefinder, a system in which focus data are provided to the operator, but adjustment of the optical system is still performed manually.

The speed of the AF system is highly dependent on the maximum aperture offered by the lens. F-stops of around f/2 to f/2.8 are generally considered optimal in terms of focusing speed and accuracy. Faster lenses than this (e.g.: f/1.4 or f/1.8) typically have very low depth of field, meaning that it takes longer to achieve correct focus, despite the increased amount of light.

Most consumer camera systems will only autofocus reliably with lenses that have a maximum aperture of at least f/5.6, while professional models can often cope with lenses that have a maximum aperture of f/8, which is particularly useful for lenses used in conjunction with teleconverters.

Phase detection

Phase detection (PD) is achieved by dividing the incoming light into pairs of images and comparing them. Through the lens secondary image registration (TTL SIR) passive phase detection is often used in film and digital SLR cameras. The system uses a beam splitter (implemented as a small semi-transparent area of the main reflex mirror, coupled with a small secondary mirror) to direct light to an AF sensor at the bottom of the camera. Two micro-lenses capture the light rays coming from the opposite sides of the lens and divert it to the AF sensor, creating a simple rangefinder with a base within the lens’s diameter. The two images are then analysed for similar light intensity patterns (peaks and valleys) and the separation error is calculated in order to find if the object is in front focus or back focus position. This gives the direction and an estimate of the required amount of focus ring movement.^[2]

PD AF in a continuously focusing mode (e.g. “AI Servo” for Canon, “AF-C” for Nikon, Pentax and Sony) is a closed-loop control process. PD AF in a focus-locking mode (e.g. “One-Shot” for Canon, “AF-S” for Nikon and Sony) is widely believed to be a “one measurement, one movement” open-loop control process, but focus is confirmed only when the AF sensor sees an in-focus subject. The only apparent differences between the two modes are that a focus-locking mode halts on focus confirmation, and a continuously focusing mode has predictive elements to work with moving targets, which suggests they are the same closed-loop process.^[3]

Although AF sensors are typically one-dimensional photosensitive strips (only a few pixels high and a few dozen wide), some modern cameras (Canon EOS-1V, Canon EOS-1D, Nikon D2X) feature TTL area SIR^{[citation needed]} sensors that are rectangular in shape and provide two-dimensional intensity patterns for a finer-grain analysis. Cross-type focus points have a pair of sensors oriented at 90° to one another, although one sensor typically requires a larger aperture to operate than the other.

Some cameras (Minolta 7, Canon EOS-1V, 1D, 30D/40D, Sony DSLR-A700, DSLR-A850, DSLR-A900) also have a few ‘high precision’ focus points with an additional set of prisms and sensors; they are only active with ‘fast lenses‘ with certain geometrical apertures (typically F-number 2.8 and faster). Extended precision comes from the wider effective measurement base of the ‘range finder’.

Phase detection

In each figure (not to scale), the purple circle represents the object to be focused on, the red and green lines represent light rays passing through apertures at the opposite sides of the lens, the yellow rectangle represents sensor arrays (one for each aperture), and the graph represents the intensity profile as seen by each sensor array.

Figures 1 to 4 represent conditions where the lens is focused (1) too near, (2) correctly, (3) too far and (4) much too far. The phase difference between the two profiles can be used to determine which direction and how much to move the lens to achieve optimal focus.

Phase detection system: 7 – Optical system for focus detection; 8 – Image sensor; 30 – Plane of the vicinity of the exit pupil of the optical system for photography; 31, 32 – Pair of regions; 70 – Window; 71 – Visual field mask; 72 – Condenser lens; 73, 74 – Pair of apertures; 75 – Aperture mask; 76, 77 – Pair of reconverging lenses; 80, 81 – Pair of light receiving sections;

Ultrasonic motor

An ultrasonic motor is a type of electric motor powered by the ultrasonic vibration of a component, the stator, placed against another component, the rotor or slider depending on the scheme of operation (rotation or linear translation). Ultrasonic motors differ from piezoelectric actuators in several ways, though both typically use some form of piezoelectric material, most often lead zirconate titanate and occasionally lithium niobate or other single-crystal materials. The most obvious difference is the use of resonance to amplify the vibration of the stator in contact with the rotor in ultrasonic motors. Ultrasonic motors also offer arbitrarily large rotation or sliding distances, while piezoelectric actuators are limited by the static strain that may be induced in the piezoelectric element.

One common application of ultrasonic motors is in camera lenses where they are used to move lens elements as part of the auto-focus system. Ultrasonic motors replace the noisier and often slower micro-motor in this application.

An illustration of the “Inchworm” piezo motor, which moves the normally free red-and-white striped rod longitudinally from left to right. When power is being applied on the piezo element, denoted by colour, it expands. By cyclically expanding the four parts, the rod is moved from left to right. 1 housing, 2 motive crystal, 3 locking crystal, 4 rotary part.

Stepper motor

A stepper motor or step motor or stepping motor is a brushless DC electric motor that divides a full rotation into a number of equal steps. The motor’s position can then be commanded to move and hold at one of these steps without any feedback sensor (an open-loop controller), as long as the motor is carefully sized to the application in respect to torque and speed.

Switched reluctance motors are very large stepping motors with a reduced pole count, and generally are closed-loop commutated.

Animation of a simplified stepper motor (unipolar)
Frame 1: The top electromagnet (1) is turned on, attracting the nearest teeth of the gear-shaped iron rotor. With the teeth aligned to electromagnet 1, they will be slightly offset from right electromagnet (2).
Frame 2: The top electromagnet (1) is turned off, and the right electromagnet (2) is energized, pulling the teeth into alignment with it. This results in a rotation of 3.6° in this example.
Frame 3: The bottom electromagnet (3) is energized; another 3.6° rotation occurs.
Frame 4: The left electromagnet (4) is energized, rotating again by 3.6°. When the top electromagnet (1) is again enabled, the rotor will have rotated by one tooth position; since there are 25 teeth, it will take 100 steps to make a full rotation in this example.

 

人為之發想大體只受限當時工藝矣！！？？