Dealing with propositions, not with the characters: the ability of three-taxon statement analysis to recognise groups based solely on ‘reversals’, under the maximum-likelihood criteria

Three-taxon statement matrices can be analysed using the maximum-likelihood method. In the present paper, it is demonstrated that groups based solely on putative reversals are always recognisable after maximum-likelihood analysis of three-taxon statement matrices, even without a priori recoding of the putative reversals as new character states or fractional weighting of three-taxon statements. Parametric implementations of three-taxon statement analysis still require more investigation. However, it must be highlighted that a focus on the set of hypotheses, rather than on the ‘actual data’, is required.

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ANALISIS TINGKAT SEISMISITAS DAN TINGKAT KERAPUHAN BATUAN DI MALUKU UTARA

JURNAL ILMIAH SAINS ◽

10.35799/jis.15.2.2015.9224 ◽

2015 ◽

Vol 17 (1) ◽

pp. 94

Author(s):

Vienda Gaby Lumintang ◽

Guntur Pasau ◽

Seni J Tongkukut

Keyword(s):

Maximum Likelihood ◽

Maximum Likelihood Method ◽

B Value ◽

Likelihood Method ◽

Earthquake Catalog ◽

Maximum Likelihood Analysis ◽

Repetition Period ◽

Earthquake Recurrence ◽

A Value ◽

Likelihood Analysis

ANALISIS TINGKAT SEISMISITAS DAN TINGKAT KERAPUHAN BATUAN DI MALUKU UTARA ABSTRAK Telah dilakukan penelitian untuk menentukan tingkat seismisitas dan tingkat kerapuhan batuan melalui perhitungan nilai a dan b secara spasial di Maluku Utara menggunakan katalog gempa ANSS tahun 1963-2015 dengan metode maksimum likelihood, menghitung kemungkinan waktu terjadinya kembali gempa bumi merusak secara spasial, serta untuk menenentukan daerah-daerah yang sangat rawan berpotensi gempa merusak di wilayah Maluku Utara. Perhitungan nilai a dan b dari data ANSS untuk wilayah Maluku Utara menunjukkan besar nilai b adalah berkisar pada 0,75-1,5 dan nilai a adalah berkisar pada 6,5-10. Periode ulang gempa bumi untuk wilayah Maluku Utara dengan magnitude Mw = 6,5 adalah 3-19 tahun, gempa dengan magnitude Mw = 7 adalah 5-52 tahun, dan gempa dengan magnitude Mw = 7,5 adalah 15-140 tahun. Daerah-daerah yang berpotensi mengalami gempa bumi merusak adalah wilayah Laut Maluku, Ternate, Tidore, sebagian wilayah Kabupaten Halmahera Utara dan Barat, Pulau Kasiruta dan Pulau Obi. Kata kunci: nilai-b, seismisitas, maximum likelihood ANALYSIS OF SEISMICITY LEVEL AND ROCKS FRAGILITY LEVEL IN NORTH MALUKU ABSTRACT A research has ben conducted to determine the seismicity level and rocks fragility level through spatially calculation of a value and b value in North Maluku using ANSS earthquake catalog of years 1963-2015 with maximum likelihood method, spatially calculate possible time of destructive earthquake recurrence, and to determine areas that highly prone to potentially destructive earthquake in North Maluku. A value and b value calculation of ANSS data of North Maluku region shows that b value is in the range of 0.75-1.5 and a value is in the range of 6.5-10. Earthquake repetition period of North Maluku region based on ANSS data with magnitude Mw = 6.5 is 3-19 years, for earthquake with magnitude Mw = 7 is 5-52 years and for earthquake with magnitude Mw = 7.5 is 15-140 years. Areas that potentially have destructive earthquake is Molucca Sea region, Ternate, Tidore, parts of North and West Halmahera District, Kasiruta Island and Obi Island. Keywords: b value, seismicity, maximum likelihood

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Eccentricity Parameters Identification for a Motorized Spindle System Based on Improved Maximum Likelihood Method

Shock and Vibration ◽

10.1155/2020/5491957 ◽

2020 ◽

Vol 2020 ◽

pp. 1-10

Author(s):

Wengui Mao ◽

Chaoliang Hu ◽

Jianhua Li ◽

Zhonghua Huang ◽

Guiping Liu

Keyword(s):

Maximum Likelihood ◽

Measurement Errors ◽

Maximum Likelihood Method ◽

Search Algorithm ◽

A Priori ◽

Likelihood Method ◽

Step Size ◽

Spindle System ◽

Grinding Machine ◽

Search Interval

As a kind of rotor system, the electric spindle system is the core component of the precision grinding machine. The vibration caused by the mass imbalance is the main factor that causes the vibration of the grinding machine. Identifying the eccentricity parameters in an electric spindle system is a key issue in eliminating mass imbalances. It is difficult for engineers to understand the approximate range of eccentricity by experience; that is, it is difficult to obtain a priori information about eccentricity. At the same time, due to the geometric characteristics of the electrospindle system, the material factors and the randomness of the measurement response, these uncertain factors, even in a small case, are likely to cause large deviations in the eccentricity recognition results. The search algorithm used in the maximum likelihood method to identify the eccentricity parameters of the electrospindle system is computationally intensive, and the sensitivity in the iterative process brings some numerical problems. This paper introduces an Advance-Retreat Method (ARM) of the search interval to the maximum likelihood method, the unknown parameter increment obtained by the maximum likelihood method is used as the step size in the iteration, and the Advance-Retreat Method of the search interval is used to adjust the next design point so that the objective function value is gradually decreasing. The recognition results under the three kinds of measurement errors show that the improved maximum likelihood method improves the recognition effect of the maximum likelihood method and can reduce the influence of uncertainty factors on the recognition results, and the robustness is satisfactory.

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