• Journal of the Korea Institute of Information Security & Cryptology
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• v.26 no.2
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• pp.387-396
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• 2016

As the number of people using digital devices has increased, the digital forensic, which aims at finding clues for crimes in digital data, has been developed and become more important especially in court. Together with the development of the digital forensic, the anti-forensic which aims at thwarting the digital forensic has also been developed. As an example, with anti-forensic technology the criminal would delete an digital evidence without which the investigator would be hard to find any clue for crimes. In such a case, recovery techniques on deleted or damaged information will be very important in the field of digital forensic. Until now, even though EVTX(event log)-based recovery techniques on deleted files have been presented, but there has been no study to retrieve event log data itself, In this paper, we propose some recovery algorithms on deleted or damaged event log file and show that our recovery algorithms have high success rate through experiments.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.4
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• pp.777-785
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• 2016

IM(Instant Messenger) chatting service can carry user's various information including life style, geographical position, and psychology & crime history and thus forensic analysis on the IM service is desirable. But, forensic analysis for KakaoTalk's chatting service is not well studied yet. For this reason, we study KakaoTalk's forensic analysis focusing on chatting service. This paper first details a general method of IM forensics investigating the previous articles about IM forensics although there are not many articles. Second, we discuss methodologies for IM forensics wherein we present analysis of table structure and method for reconstruction of chatting message. These result in the basic element of forensic tools of KakaoTalk chatting message. Last, we compare artifacts of KakaoTalk with that of WhatsApp. We conclude that these applications are, at least, different in that table structures and the ways to reconstruct chatting messages are not same and therefore digital evidences or artifacts are not same and somewhat distinct.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.235-239
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• 2010

Use of mobile phones reached saturation point, the recent use of the iPhone, including the Smart Phone is increasing rapidly. How to extract forensic data from current mobile phones and SYN, JTAG, Revolving There are three ways. Mobile phone and Smart Phone, but the technology and how to use forensic data because of the difference must have different extraction methods. In this paper, in the Smart Phone will study how to extract forensic data. Commonly used in the Google Android Smart Phone and Windows Mobile Smart Phone OS in the specification and analysis for analysis, the data analysis. Also, Google Android and Windows Mobile Smart Phone to extract forensic data to generate evidence. The present study tested the Mobile Smart Phone technology research will contribute to the development of forensic techniques.

• Journal of the Korean Society of Safety
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• v.28 no.5
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• pp.15-20
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• 2013

This paper dealt with melting characteristics of low-voltage miniature cartridge fuse used for 220 V electronic equipment. The experimental sample is low-voltage miniature cartridge fuse with rating of 250 V(3A) and size of $5{\times}20$ mm. In order to evaluate melting and scattering characteristics of the fuse, we applied to 8/20 ${\mu}s$ surge current, overload current and external thermal stress such as flame of fire. From the experimental results, the fuse element was melted and scattered by applied surge current(above 0.79 kA) and overload current(above 4.5 A). It was also attached to the inner surface of the fuse tube. The fuse element was attached as a thin film on inner surface of fuse tube when large surge current was applied. It was confirmed, however, the fuse element was not changed by external thermal stress such as flame and hot-air.

• Environmental Analysis Health and Toxicology
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• v.20 no.4 s.51
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• pp.297-302
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• 2005

The purpose of this study was to provide the standard method for the analysis of organophosphorous pesticides such as chlorpyrifos, diazinon, malathion and parathion in blood. We performed method validation for these pesticides in blood according to EURACHEM (A focus For Analytical Chemistry in Europe) guide. For the analysis of the pesticides, we used solid-phase extraction ,column (Waters Oasis $HLB^{(R)}$. After the extraction, the supernatants were evaporated to dryness under the nitrogen stream. They were analyzed by gas chromatography/mass spectrometry (GC/MS) after reconstituting with ethanol. Terbufos was used as an internal standard. To validate this method, we performed verification procedures with the following parameters: selectivity, linearity of calibration, accuracy, precision, limit of detection and quantification. Validation data according to Eurachem guide were adequate for our purpose for the analysis of chlorpyrifos, diazinon, malathion and parathion in blood.

• Journal of Welding and Joining
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• v.34 no.5
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• pp.47-53
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• 2016

The aim of this study is to consider effect of weld elastic modulus on simulations of stress concentration and fatigue life for pressure vessel. The investigations include analysis with ADINA and WINLIFE softwares for whole body model about using condition of the boiler vessel. Values of weld elastic modulus were divided by 5 steps in butt weld area of the boiler vessel body. The stress concentration of the butt weld more was increased in case of higher elastic modulus of weld area because of higher difference of material properties between matrix and weld. It was concluded that the fatigue lives were decreased along increasing stress concentration due to high elastic modulus of weld. The matrix microstructure was estimated as pearlitic structure of ${\alpha}$ ferrite and pearlite. And the microstructures of welds along 5 steps of elastic modulus were estimated as bainitic fine pearlite and martensite as increasing elastic modulus.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.05a
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• pp.207-210
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• 2014

Damage is increasing by (Smishing) hacking attack Smishing you use a smart phone after entering 2013. Takeover of personal information and direct financial damage in collaboration with graphics sewing machine hacking attack has occurred. Monetary damage that leads to Internet payment service (ISP) and secure payment system in conjunction with graphics sewing machine hacking attack on a smartphone has occurred. In this paper, I will study analysis in the laboratory examples of actual infringement vinegar sewing machine hacking attack. It is a major power security measures to prevent damage to the secure payment system that a case analysis and practical principle technical nest sewing machine hacking attack, using Smishing. In this paper, I will be to research to be able to through a smart phone, to the online payment safer and more convenient.

• Applied Chemistry for Engineering
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• v.29 no.3
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• pp.356-361
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• 2018

It is common to analyze volatile organic compound (VOC) or semi-VOC (SVOC) in a sample composed of a complex matrix consisting of multiple components such as bloods through a separation process. Adsorption is a physical phenomenon in which certain components accumulate on the surface of other phases. In order to overcome difficulties in the pretreatment process, an adsorption is frequently used. Solid phase microextraction (SPME) equipment with porous carbon carboxen (CAR) is an example of adsorption application. In this study, the adsorption of 4-octylphenol to carboxen was examined. To do so, the extraction efficiency for such solvents as dichloromethane ($CH_2Cl_2$, DCM), ethylacetate ($CH_3COOC_2H_5$, EA) and diethylether ($C_2H_5OC_2H_5$, $Et_2O$) was studied and also the derivatization reaction for 4-octylphenol with reagents of bistrimethylsilyltrifluoroacetamide (BSTFA), methylchloroformate (MCF) and pentafluorobenzylbromide (PFBBr) was compared. The combination of DCM and BSTFA showed good performance thus they were adopted for this study. Thermodynamic adsorption experiments showed that the adsorption process was endothermic and Freundlich isotherm equation was more suitable than Langmuir isotherm. It was also found that the adsorption followed a pseudo-$2^{nd}$ order kinetic model.

• Analytical Science and Technology
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• v.29 no.2
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• pp.73-78
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• 2016

Hydrogen cyanide (HCN) is an extremely toxic gas frequently produced during the incineration of plastics, such as acrylonitrile-butadiene-styrene (ABS). A victim of a fire who has inhaled smoke could have cyanide in the blood. Therefore, cyanide could be a good marker for a post-mortem examination of a fire as well as carboxyhemoglobine (COHb) test of blood samples. For a particular fire case, a burned body with a suicide note was found inside a burned vehicle. Even though the COHb value is conclusive evidence, measuring the COHb for denatured blood might be difficult due to severe thermal denaturation or the formation of methemoglobin (MetHb). To overcome this difficulty, cyanide could be used as an indicator when investigating the death of a fire victim. In this study, gas chromatography/mass spectrometry (GC/MS) was adopted to measure the levels of cyanide in the blood through derivatization with pentafluorobenzyl bromide (PFBBr) under cation surfactant by scan and SIM mode. The concentration of cyanide in the blood of heart blood and brain of the victim was found to be 0.36 µg/mL and 1.20 µg/mL respectively, which was higher than the average value (0.041 µg/mL) found in the blood of 14 people who smoked.

• Journal of Digital Convergence
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• v.13 no.4
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• pp.81-87
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• 2015

This study will show the digital forensic model which fights against cyber-crimes to prepare various cyber-crimes. The digital forensic model will be more useful about the investigation of cyber-crimes and arresting criminals after researching the uses of the digital forensic model and cyber-crime rates in South Korea. This model conduct the standardized data with various languages by the language support system through the digital forensic analyzer. This model will send the data to law enforcement reviewing whether or not we ought to prove criminal charges. Moreover, law enforcement can access the file system to find out admissibility of evidence. And this model simplifies lawful investigation about additional investigation. The data, which is conducted and saved by the digital forensic system, will be helpful to protect against the future crimes because of the data.