Earticle

In digital forensics, searching for specific patterns in binary data is a crucial task almost always performed following data acquisition. As the volume of digital data surges and the capacity of storage media expands, there is an increasing demand for search techniques that ensure accuracy, completeness, and speed. In this paper, we explore methods to enhance search efficiency through multi-threading and memory-mapped files, while also improving the completeness of searches in corrupted data by adjusting the search resumption position after a match is found. By employing multi-threading, the parallel utilization of multiple processor cores increases the computational speed. Additionally, while some threads occupy the processor, others can access the storage medium, reducing idle times for the storage medium, and thereby maximizing the utility of the storage medium's read speed. Memory-mapped files enable direct access to the operating system’s memory region associated with the storage medium, minimizing the caching and copying stages. This reduces computational overhead and memory load compared to standard file input/output operations. In 64-bit systems, memory-mapped files allow access to files larger than physical memory as a contiguous virtual memory space of up to 2⁶⁴ bytes (16,777,216 terabytes), enabling memory-based implementations of search algorithms to be applied to large files without modification. Experimental results show that the proposed approach significantly enhances both the speed and accuracy of searches in large files, outperforming a method that relies on single-threading and standard file input/output.

This study proposes and implements a blockchain based system to ensure the integrity of digital evidence. Digital evidence plays a crucial role in legal disputes and criminal investigations, However conventional centralized systems are vulnerable to data tampering and loss. To address these challenges, this research designs a system that guarantees the integrity of digital evidence throughout the processes of collection, storage, and verification by utilizing a private blockchain. This paper begin by examining blockchain and various consensus algorithms, followed by a detailed description of the implementation methods and processes of the proposed system. The system employs Ethereum-based GoQuorum to construct the private blockchain. Also, the QBFT consensus algorithm used in this network provides high security and fast processing speeds. By developing the smart contract, we enabled the storage and retrieval of the generated hash value of digital evidence on the blockchain. Our System verifies integrity by comparing the hash value stored on the chain with the hash value of the original image. Consequently, the blockchain-based integrity verification system has contributed to enhancing the reliablility of digital evidence and has improved both efficiency and security in legal proceedings.

STR typing of crime scene evidence is currently contributing to solving various cases. In a autopsy case, the identity of the body is confirmed by collecting blood and comparing the STR typing results of the deceased with those of the family. This study, the rapid DNA extraction reagent was used to purify DNA from autopsy samples, blood and costal cartilage, and the effect of the rapid DNA extraction reagent on STR type was examined by comparing it with standard DNA. As a result of the experiment, the average DNA concentration using the rapid extraction reagent was purified to 0.277 ng/㎕ for blood and 0.069 ng/㎕ for costal cartilage, which met the recommended DNA concentration of 0.050 ng/㎕ for the STR amplification kit. The DNA degradation index was confirmed to be a maximum of 1.703 for blood and 0.660 for costal cartilage. In the case of STR type detection, DNA types were detected in all blood and costal cartilage samples. In the balance comparison of the values of heterozygous loci, there was no significant difference in the analysis values compared to the standard DNA samples, with 3 loci in blood, 6 loci in costal cartilage, and 6 loci in 007.

Even though vehicles are important means of transportation in modern society, they are accompanied by lots of traffic accidents. Sudden unintended acceleration(SUA) is supposed to be one of them. This study investigates the effect of lubricating system of vehicle equipped with turbocharger on SUA from two perspectives which are the quality and quantity of the lubricating oil system. The diluted lubricating oil with diesel oil didn't show deteriorating effect on the consistency of turbocharger at normal quantity. However, excessive quantity of oil showed dramatic effect on engine performance of exhausting white smoke with noise and vibration. This malfunction was thought to be from the flow of lubricating oil through blowby gas ventilation system into combustion chamber. Lest the problem should happen, lubrication management of vehicles is thought to be necessary for both sides of the quality and quantity of the lubricating oil.

Toluene is an aromatic hydrocarbon widely employed as an industrial solvent in adhesives and paints. Due to its broad availability and low cost, it ranks among the most frequently abused volatile substances worldwide. With repeated inhalation, toluene affects the central nervous system, inducing euphoria, intoxication, and hallucination, while its high lipophilicity facilitates penetration of the blood–brain barrier and accumulation in lipid-rich tissues. Given these properties, high-dose inhalation of toluene may lead to direct fatal intoxication, as well as indirect fatalities arising from accidents associated with hallucinatory impairment. In most toluene-related deaths, toxicological interpretation typically relies on scene investigation, the presence of paraphernalia, and reported blood concentrations of toluene. However, in indirect fatalities, interpretation based solely on blood toluene concentrations remains controversial due to ongoing biological processes. In this study, we investigated a fatal case involving a 56-year-old male with a history of toluene abuse. Postmortem specimens, including heart blood, peripheral blood, urine, lung and brain tissue, were analyzed for toluene using solid-phase microextraction gas chromatography–mass spectrometry (SPME-GC/MS) with a standard addition method. Toxicological analysis revealed a markedly elevated concentration of toluene in brain tissue (10.04 mg/kg). Heart and peripheral blood contained 1.94 mg/L and 1.27 mg/L of toluene, respectively. Urine and lung tissue exhibited a relatively low concentrations of 0.14 mg/L and 1.89 mg/kg, respectively. This case analysis, based on an understanding of the distributional characteristics and toxicological mechanisms of toluene, suggests the forensic interpretability of volatile hallucinogenic substances as potential indirect causes of death and is expected to contribute to toxicological assessments in future similar cases.

In order to simplify and reduce the cost of the analysis process for reference samples, STR typing using direct PCR buffer was confirmed. To select an efficient buffer, STR typing was performed using two kinds of buffers. As a result of comparing the STR full profile detection rate and peak height through the heat treatment-based rapid extraction method of the reference samples, it was confirmed that STR GO! was more efficient than Prep-n-Go. In addition, when using commercially available STR and Y-STR analysis kits (GlobalFiler, PowerPlex Fusion, Y23), it was found that there was no problem in result analysis even if the PCR reaction volume for DNA extracted with STR GO! was reduced to 10 uL. However, the detection rate of STR profiles decreased in DNA that had passed time after extraction. To overcome this, the dilution ratio of the PCR amplification product was adjusted and it was confirmed that there was no problem with STR typing even 4 weeks after extraction. This study is expected to be of great help in simplifying and reducing costs of STR typing for reference samples.

The development of forensic science has significantly contributed to the resolution of criminal cases and the accuracy of legal judgments through the utilization of scientific evidence. In particular, the use of DNA barcoding to identify plant and animal species in forensic science has become an essential and reliable method because it can accurately distinguish species that are difficult to distinguish by morphological characteristics alone. However, in the case of rice species identification, it was confirmed that DNA barcoding, which primarily targets regions with low intra-species variation due to the characteristics of rice breeding development in Korea, has certain limitations. In this study, focused on an embezzlement case involving rice species identification, evaluated the limitations of three conventional DNA barcodes and five rice-specific DNA barcodes in forensic analysis. To address these limitations, we evaluated the applicability of a commercially developed rice species identification kit based on single nucleotide polymorphism (SNP) identification technology. The application of the commercial kit in rice species identification demonstrated high sensitivity and specificity, even with small amounts of test samples. Additionally, it allowed for the determination of rice species in a shorter time frame compared to traditional DNA barcoding methods. As a results, the application of commercial kits in future cases related to rice species identification may help to serve as an reliable forensic biology analysis.

Synthetic cannabinoids (SCs) are the most abused new psychoactive substances. Although fatal cases related to SCs have been reported in multiple countries, reports on blood concentrations associated with intoxication are limited. Over the past three years, ADB-BUTINACA was detected in two individual fatal cases in Korea. This study presents the blood concentrations of ADB-BUTINACA in these cases. Blood samples were treated with methanol to precipitate proteins. The screening and quantitative analysis were performed by liquid chromatography-tandem mass spectrometry with electrospray ionization in the positive ion mode. Both the limits of detection and the limits of quantification for ADB-BUTINACA were 0.5 ng/mL. Validation results showed good linearity in the range of 0.5-50 ng/mL. ADB-BUTINACA was detected and quantified in cardiac blood and peripheral blood of two individual fatal cases. The determined concentration of ADB-BUTINACA were 33.40 ng/mL and 11.56 ng/mL in cardiac blood, 14.73 ng/mL and 13.75 ng/mL in peripheral blood, respectively. Along with parent form of ADB-BUTINACA, its metabolites were analyzed. In one case ADB-BUTINACA 3,3-dimethylbutanoic acid metabolite was detected and the concentration of the metabolite were 1.44 ng/mL in cardiac blood, 1.96 ng/mL in peripheral blood. Due to lack of previous published reports on blood concentrations of ADB-BUTINACA in fatal cases, toxicological assessment remains challenging. The findings from these authentic cases are expected to serve as an important reference for future forensic investigations.

Fentanyl analogs are highly potent synthetic opioids active at very low doses and have been implicated in numerous overdose deaths, particularly in the United States. Although serious social problems caused by the abuse of fentanyl analogs have not yet been reported in Korea, possibly remains a risk of their introduction into the country. Thus, the establishment of analytical methods for fentanyl analogs in biological samples has become necessary. In this study, we developed simultaneous analytical methods for the detection of 22 fentanyl analogs and their metabolites in human hair using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Specificity, selectivity, limits of detection (LOD), limits of quantification (LOQ), linearity, precision, accuracy, matrix effect, recovery, and process efficiency were evaluated, and all results were acceptable. Additionally, the distribution of fentanyl analogs in the hair of drug abusers from 2020–2024 was investigated. Fentanyl was detected in 204 cases, with the highest frequency observed in 2021, followed by a decreasing trend in subsequent years. A rare case involving both fentanyl and remifentanil was identified in the hair of a 48-year-old female nurse, demonstrating the applicability of this method for detecting fentanyl analogs in forensic investigations.