若是仔細觀察『地壘』之 Signal/Noise/History 圖

 

當可知道即使在『固定』位置，所測得的『 RSSI 』也像是『隨機』的勒！？一張典型 RF 發射系統圖，也許足以說明這個『不確定性』的由來︰

 

 

或許另一張實測圖︰

引自《 Indoor Localization using Multiple Wireless Technologies 》論文

 

更能清楚了解那些數值的『機率分佈』。如此我們當知 RSSI 的數據必須經過『處理』，方能代表某種『  』尺度，而且還得『校正 』才能表達『□□』的吧！那個『數據』的『時間序列』本身

宛如起伏之波瀾，正待適當『模型』的詮釋哩！！

如是看來這麼個『簡單定向器』也『不簡單』的耶？那麼我們將要如何用這根 RSSI 『尺』的呢？又怎樣能夠得到下面的圖的呢？？

 

 

俗話說︰有煙 必有火，無風不起浪。是否『煙』可以作『火』的『指標』？『浪』一定是『風』引起的呢？？相繼的現象，伴隨的關係常為『徵候』的由來，卻未必有『物理因 果』性。雖說大多數物質『熱脹冷縮』，水結冰、冰化水，卻是『冷漲熱縮』！更別講此一現象對水中生物之生存重要性的哩！！所以當我們談到度量的『 』尺，就必須注意『現象』的『重複性』、『再現性』……『可靠性』的概念區分。此處引用維基百科相關詞條︰

Repeatability

Repeatability or test–retest reliability^[1] is the variation in measurements taken by a single person or instrument on the same item, under the same conditions, and in a short period of time. A less-than-perfect test–retest reliability causes test–retest variability. Such variability can be caused by, for example, intra-individual variability and intra-observer variability. A measurement may be said to be repeatable when this variation is smaller than a pre-determined acceptance criteria.

Test–retest variability is practically used, for example, in medical monitoring of conditions. In these situations, there is often a predetermined “critical difference”, and for differences in monitored values that are smaller than this critical difference, the possibility of pre-test variability as a sole cause of the difference may be considered in addition to, for examples, changes in diseases or treatments.^[2]

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Reproducibility

Reproducibility is the ability of an entire experiment or study to be duplicated, either by the same researcher or by someone else working independently. Reproducing an experiment is called replicating it. Reproducibility is one of the main principles of the scientific method.

The values obtained from distinct experimental trials are said to be commensurate if they are obtained according to the same reproducible experimental description and procedure. The basic idea can be seen in Aristotle‘s dictum that there is no scientific knowledge of the individual, where the word used for individual in Greek had the connotation of the idiosyncratic, or wholly isolated occurrence. Thus all knowledge, all science, necessarily involves the formation of general concepts and the invocation of their corresponding symbols in language (cf. Turner). Aristotle′s conception about the knowledge of the individual being considered unscientific is due to lack of the field of statistics in his time, so he could not appeal to statistical averaging by the individual.

A particular experimentally obtained value is said to be reproducible if there is a high degree of agreement between measurements or observations conducted on replicate specimens in different locations by different people—that is, if the experimental value is found to have a high precision.^[1]

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Reliability

In the psychometrics, reliability is the overall consistency of a measure. A measure is said to have a high reliability if it produces similar results under consistent conditions. For example, measurements of people’s height and weight are often extremely reliable.^[1][2]

Types

There are several general classes of reliability estimates:

• Inter-rater reliability assesses the degree of agreement between two or more raters in their appraisals.
• Test-retest reliability assesses the degree to which test scores are consistent from one test administration to the next. Measurements are gathered from a single rater who uses the same methods or instruments and the same testing conditions.^[2] This includes intra-rater reliability.
• Inter-method reliability assesses the degree to which test scores are consistent when there is a variation in the methods or instruments used. This allows inter-rater reliability to be ruled out. When dealing with forms, it may be termed parallel-forms reliability.^[3]
• Internal consistency reliability, assesses the consistency of results across items within a test.^[3]

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方便讀者對比意義的差別，或將發現建立 RSSI 『尺度』之法的耶 ！？