Implementing an optimization algorithm to estimate the time of death considering environmental temperature variations

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Abstract

During forensic determination of the postmortem interval based on thermometric examination of a body, there may be cases where the ambient temperature at the discovery site has changed over time. In such cases, using the environmental temperature measured at the time of body examination for calculations inevitably leads to errors in estimating the time of death. However, forensic medicine has developed a method that allows calculations under incomplete initial data conditions by optimizing the variables used as predictors in the mathematical model underlying the estimation. This approach is demonstrated through a case study presented in the article.

Using Powell’s optimization algorithm, the study illustrates a formula-based calculation of the postmortem interval when the ambient temperature recorded at the time of examination differs from that during the period the body remained at the discovery site. A computational sheet was developed in Microsoft Excel with numbered cells containing the necessary formulas, making it applicable in forensic medical practice. This approach can be further implemented in the Calc application from the LibreOffice suite or similar software.

In the article presents a practical example of body examination at the discovery site, including rectal thermometry results and postmortem interval calculations without the optimization-based approach for determining individual coefficient values. The case report demonstrates that an expert approach to assessing initial values in a specific investigative context can significantly enhance the accuracy of determining the postmortem interval. This conclusion is supported by the alignment of calculated postmortem interval values with the results obtained through investigative methods.

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About the authors

Alexey Yu. Vavilov

Izhevsk State Medical Academy

Author for correspondence.
Email: izhsudmed@hotmail.com
ORCID iD: 0000-0002-9472-7264
SPIN-code: 3275-3730

MD, Dr. Sci. (Medicine), Professor

Россия, Izhevks

Airat А. Khalikov

Bashkir State Medical University

Email: airat.expert@mail.ru
ORCID iD: 0000-0003-1045-5677
SPIN-code: 1895-7300

MD, Dr. Sci. (Medicine), Professor

Россия, Ufa

Tatiana V. Naidenova

Izhevsk State Medical Academy

Email: abhasvar@mail.ru
ORCID iD: 0000-0001-7847-4706
SPIN-code: 7697-5731

MD, Cand. Sci. (Medicine)

Россия, Izhevks

References

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  4. Vavilov AYu, Belykh SA, Shved EF. Mathematical simulation of the corpse’s temperature changes during exposure of a direct solar radiation to diagnose a postmortem interval. Sudebno-meditsinskaia ekspertiza = Forensic medical expertise. 2023;66(6):18–23. EDN: IJTJZD doi: 10.17116/sudmed20236606118
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  12. Viter VI, Vavilov AYu, Babushkina KA, Khokhlov SV. The work procedure of a doctor-forensic expert when examining a corpse at the place of its discovery: A training manual. Izhevsk; 2016. 88 p. (In Russ.)
  13. Kildyushov ЕМ, Vavilov АYu, Kulikov VА. Diagnosis of time of death using thermometric method in early postmortal period (new medical technology). Bulletin of forensic medicine. 2012;1(1):19–23. EDN: PIVYGP
  14. Panteleev AV, Letova TA. Optimization methods in examples and problems: Textbook for university students. Moscow: Vysshaya shkola; 2002. 544 p. EDN: SBRINH

Supplementary files

Supplementary Files
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2. Fig. 1. Graphical representation of the optimization algorithm for calculating the time of death using the thermometric method.

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3. Fig. 2. Sheet with formulas for calculating time since death based on the optimization algorithm.

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4. Fig. 3. Result of applying the optimization algorithm.

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