New computer technologies to determine postmortem interval by the Henssge method

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Abstract

Background: The Henssge method is still the main thermometric method to determine postmortem interval. However, its existing software implementations are characterized by several disadvantages associated with copying simplified nomographic variants of the original mathematical models without any optimization attempts, as well as procedural imperfection in finding the roots of implicit functions. In this paper, methods are proposed for optimizing solutions to the Henssge mathematical models and determine their errors, as well as software application implementation. Aim: Optimization of the Henssge algorithm and development of a series of applications based on the obtained data, designed to determine postmortem interval. Material and methods: Methods for solving double exponential Henssge models and determining their errors based on computational mathematics and regression modeling using the least-squares method with subsequent implementation in the format of computer programs in C# language optimized. Results: The discrete nature of residual variance changes of the double exponential Henssge models intended to determine the postmortem interval according to rectal and cranioencephalic thermometry data under constant external temperature conditions is eliminated. The interval estimate determination of postmortem interval at any confidence probability is possible. The application program Warm Bodies HR was developed, which implements applied optimization methods. The application program Warm Bodies AHBG, designed to determine postmortem interval by the Henssge method in a single discrete decrease or increase conditions in the constant temperature of the external environment, including a change in the cooling conditions of the corpse, was developed. The search for the roots of implicit functions in programs is carried out using the Newton tangent method, which ensures continuous source data nature and eliminates errors associated with the need to round directly measured physical quantities. Conclusions: The developed programs are recommended for forensic medical expert practice to determine postmortem interval.

About the authors

German V. Nedugov

Samara State Medical University

Author for correspondence.
Email: nedugovh@mail.ru
ORCID iD: 0000-0002-7380-3766
SPIN-code: 3828-8091
Scopus Author ID: 25947646500
ResearcherId: ABH-5590-2020

MD, Cand. Sci. (Med.), Assistant Professor

Russian Federation, 89 Chapaevskaya st., Samara, 443099

References

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Supplementary files

Supplementary Files
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1. JATS XML
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2. Fig. 1. The residual standard deviation of the Henssge model dependence on the dimensionless temperature at ambient temperatures up to 23.2°C and standard cooling conditions of the corpse.

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3. Fig. 2. The residual standard deviation of the Henssge model dependence on the dimensionless temperature at an ambient temperature above 23.2°C under non-standard cooling conditions of the corpse

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4. Fig. 3. The start window of the Warm Bodies HR application with a non-editable drop-down list of available diagnostic points.

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5. Fig. 4. The start window of the Warm Bodies AHBG program with the entered data from Example 2.

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Copyright (c) 2021 Nedugov G.V.

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This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.

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