• Korean Chemical Engineering Research
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• v.55 no.1
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• pp.135-140
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• 2017

This paper is on a study for discrimination on relative sequence as a most actively discussed topic in forensic document fields. This paper describes the application of the visual spectral comparator and infinite focus microscope as observation methods for overlapping region of printing and writing lines. As a result, we could categorize overlapping region images and identify the sequence of printing and writing lines by various inks.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.11
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• pp.1283-1290
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• 2014

Recently, a wide variety of simulation techniques such as structure analysis and structure-fluid interaction analysis are being employed in the field of forensic engineering for resolving the problem of legal liability for accidents and disasters. In this study, we performed a forensic engineering investigation of a sinking accident of a DCM (deep cement mixing) vessel. The accident vessel was built as a dedicated SCP (sand compaction pile) vessel at the time of vessel building, and the DCM vessel was structurally modified, e.g., by increasing the leader height and constructing for leader expansion, without a stability review. To determine the effects of expansion and modification of structures in this sinking accident, structural stability evaluation was performed using commercial software for structural analysis, ADINA software. Through an analysis and comparison of simulation results obtained using ADINA software with the results of the structural modification and expansion, we could determine the exact cause of the sinking accident of the DCM vessel.

• Child Health Nursing Research
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• v.26 no.1
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• pp.82-89
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• 2020

Sudden infant death syndrome (SIDS) in Korea remains a poorly-understood subject for both professionals and the public. Recent reports have emphasized ethnic differences in SIDS rates, suggesting that making adjustments in child-rearing practices may contribute substantially to SIDS reduction. Two of the three major risk factors for SIDS-vulnerability of the infant and exogenous factors-need to be understood in particular depth due to their broad scope and sociocultural grounding. This paper presents substantial issues regarding preterm birth and male gender on infants' vulnerability to SIDS in Korea. Practices of caring for healthy infants are addressed in the context of sleeping practices, including sleeping position, bedding arrangements, sleeping on the floor, the back-to-sleep position, high indoor temperatures and ondol floor heating, and swaddling. Professional and social awareness about how to reduce SIDS should be raised by promoting a better understanding of risk factors in the context of ethnic and cultural variations in child-rearing practices.

• Korean Journal of Materials Research
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• v.27 no.3
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• pp.172-178
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• 2017

The aim of this study is to consider the effect hydrogen on dezincification behavior of Cu-Zn alloys. The investigations include microstructural observations with scanning electron microscope and chemical composition analysis with energy dispersive spectrometer. The dezincification layer was found to occur in high pressure hydrogen atmosphere, not in air atmosphere. In addition, the layers penetrated into the inner side along the grain boundaries in the case of hydrogen condition. The shape of the dezincification layers was porous because of Zn dissolution from the ${\alpha}$ or ${\beta}$ phase. In the case of stress corrosion cracks formed in the Cu-Zn microstructure, the dezincification phenomenon with porous voids was also accompanied by grain boundary cracking.

• Transactions on Electrical and Electronic Materials
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• v.18 no.4
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• pp.221-224
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• 2017

This paper dealt with the extraction of series arc signals based on wavelet transform in order to improve the accuracy of arc detection in indoor wiring systems. Three types of arc sources including a cord-cord, a terminal-cord, and an outlet-plug were fabricated to simulate typical arc defects. An arc generator fabricated according to UL 1699 was used to generate arcs. The optimal mother wavelet was selected as bior1.5 by calculating the correlation coefficients between the detected single current pulse and the wavelet. The detected arc current signals were then decomposed into eight levels using the discrete wavelet transform that implements the multi-resolution analysis method. By analyzing the decomposed components, the detail components D6, D7, and D8 were associated with arc signals, which were used for signal reconstruction. From the result, it was verified that the proposed method can be used for the extraction of the series arc signal from the AC mains, which is expected to be applied to further analysis of arc signals in indoor wiring systems.

• The Korean Journal of Legal Medicine
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• v.42 no.4
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• pp.168-171
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• 2018

In Korea, small octopus (Octopus minor) and webfoot octopus (Octopus ocellatus) are food items and fatal laryngeal choking due to ingestion of live octopus is not uncommon. We recently encountered two autopsy cases of accidental choking on small octopus and webfoot octopus. Case 1 involved a 58-year-old fisherman who ingested two live webfoot octopuses in his fishing boat and collapsed. He was immediately taken to the hospital but died. During autopsy, one of the webfoot octopuses was found between his pharynx and esophagus; it was obstructing the epiglottis and upper esophagus. His blood alcohol concentration was 0.140%. Case 2 involved a 55-year-old man who ingested an intact body part of a small octopus and was found dead in his house. He had a history of cerebral infarction and angina pectoris. During autopsy, an intact body part of the small octopus was found to be lodged in the laryngeal inlet.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.21 no.6
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• pp.55-65
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• 2011

Recently, use of cloud computing service is dramatically increasing due to wired and wireless communications network diffusion in a field of high performance Internet technique. Cloud computing is a model for enabling convenient, on-demand network access to a shared pool of configurable computing resources (e.g., networks, servers, storage, applications, and services) that can be rapidly provisioned and released with minimal management effort or service provider interaction. In a view of digital forensic investigation, it is difficult to obtain data from cloud computing service environments. therefore, this paper suggests analysis method of AWS(Amazon Web Service) and Rackspace which take most part in cloud computing service where IaaS formats presented for data acquisition in order to get an evidence.

• Journal of the Korean Society of Safety
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• v.32 no.4
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• pp.100-106
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• 2017

Outline map is used for the description and reconstruction of the traffic accident. One way to produce the outline map is by adopting detailed measurements from the accident site such as final position of the vehicle and pedestrian, width of the road, and locations of the oil and tire marks. This method consumes large amount of time not to mention that of the production of detailed version as fine as the picture of the site. Aerial recording equipment so called HeliCam can produce an outline map that can substitute that of manual method with even faster production time and higher resolution. However, the produced picture have errors which are resulted by distortion due to the characteristics of camera and direction of the photographing. This paper provides correction of the distortion of oultline map produced by HeliCam using Adobe Photoshop and PC-Rect. The result showed resonable error range less than 6 cm(0.1%) for $60m{\times}30m$ area taken by HeliCam. The presented method develops outline map with small error, which is useful to traffic accident analysis, and traffic accident cases analyzed in this study were also.

• Tribology and Lubricants
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• v.28 no.6
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• pp.315-320
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• 2012

For proper functioning, general machines usually need lubricant oil as a cooling, cleaning, and sealing agent at points of mechanical contact. The quality of lubricant oil can deteriorate during operation owing to various causes such as high temperature, combustion products and extraneous impurities. In this study, a heavy load stopped during operation, and the oil was analyzed to check whether any impurities were added. Extraction using acetonitrile followed by reaction with BSTFA(bistrimethylsilyl trifluoroacetamide) showed that, trimethylsilylated ethylene glycol was present in the lubricant oil. To quantify the ethylene glycol in the oil, deuterium-substituted ethylene glycol, which acted as an internal standard, was added to the sample and then extracted with the solvent. Next, the extract was reacted with the derivatizing agent(BSTFA) and then analyzed with GC/MS. The detection limit of this method was found to be $0.5{\mu}g/g$ and the recovery of oil containing $20,000{\mu}g/g$ of ethylene glycol was measured to be 94.8%. A damaged O-ring and eroded cylinder liner were found during the overhaul, which implied the leakage of coolant containing ethylene glycol into the lubricating system. The erosion of the cylinder liner was assumed to be due to cavitation of the coolant in the cooling system.

• 한국정보통신설비학회:학술대회논문집
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• 2007.08a
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• pp.142-146
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• 2007

Digital Rights Management (DRM) technology has been widely used for protecting the digital contents over the recent years. But the digital contents protected by DRM are vulnerable to various video memory capture programs when DRM packaged contents are decrypted on the consumers' multimedia devices. To make up for this kind of DRM security holes the Forensic Marking (FM) technology is being deployed into the content protection area. Most leading DRM companies as well as big electronics companies like Thomson and Philips already have commercial FM solutions. Forensic Marking technology uses the digital watermarking to insert the user information such as user id, content playing time and etc. into the decrypted and decoded content at the playback time on the consumer devices. When the content containing watermarked user information (Forensic Mark) is illegally captured and distributed over the Internet, the FM detection system takes out the inserted FM from the illegal contents and informs contents service providers of the illegal hacker's information. In this paper the requirements and test conditions are discussed for the commercial Forensic Marking systems.