• Journal of Digital Forensics
• /
• v.12 no.3
• /
• pp.109-120
• /
• 2018

The smartphone is the communication device that is the most personal to the user, and it keeps a lot of information related to the user and makes information communication with other devices. With these characteristics, forensics on smartphones are one of the most basic methods of investigation in criminal investigations, and have actually contributed to the settlement of the case by providing many clues. However, recently, it is designed to encrypt data stored as a social issue related to the protection of user's personal information, or to delete deleted data or to delete log data together. So, any solutions? In this paper, I try to find the answer from cloud data stored by smartphone user account. Cloud forensics should approach complementary relationships rather than smartphone forensics. There are a lot of data stored in the cloud that can be meaningfully used in the investigation. Online activity information of users, such as Internet usage, YouTube view, and contents purchase information, cloud service such as e-mail, cloud drive, and location information are the most representative data. These data can be unvaluable, but here are some important clues in various types of criminal investigations. In this paper, I propose a method to extract data from the google cloud so that the data can be used for investigation, and to utilize the extracted data for investigation. And it explains the role of the extracted artifacts in the actual investigation business through virtual cases and proves its value.

• Journal of the Korean GEO-environmental Society
• /
• v.20 no.5
• /
• pp.31-38
• /
• 2019

Recently, there has been an increasing number of ground subsidence (sink-hole) in the downtown areas, and in such a case, it is important to minimize accidents and passages through prompt recovery. With respect to the present recovery method for ground subsidence, the methods of applying the back filling after excavating the ground subsidence or using the grouting injected materials to restore the ground are mostly used, but there has been few studies on materials used for recovering the ground subsidence. Therefore, in order to clarify the characteristics of back filling materials used in the ground subsidence, this study uses the environment-friendly hardening agent to improve the dredged clay, and then, the mixture ratio of hardening agent and mixture ratio of decomposed granite soil is changed to cure for 3, 7, 14 and 28 days to analyze the intensity characteristics of the unconfined compression, and it was compared with the unconfined compression intensity for the previously used cement, a hardening agent. In order to evaluate the characteristics of intensity on the back filling materials, the C.B.R test was carried out, and for the review on whether the back filling materials influence on corrosion of water and sewer pipes and others, the soil non-resistance test was carried out. As a result of the test, for the case of the recovery work of the ground subsidence that requires urgency, it is considered as prudent if the hardening agents of 12% are integrated to cure for 3 days or longer, and for not having the influence on the corrosion of the gas tube or water pipes, it is proposed to mix for 30% or more of the decomposed granite soil. Door model test were conducted To confirm the bearing capacity characteristics of the solidified layer.

• Journal of the Korean Society of Radiology
• /
• v.13 no.3
• /
• pp.481-487
• /
• 2019

Based on the scan conditions and algorithms that are generally applied during examinations during head CT examinations, the results of dose reduction through the application of algorithm changes were investigated through experiments. As a result, the dose reduction effect was more meaningful for the change of perfusion than for the tube voltage, and the quality evaluation using the brain phantom was relatively less reduced when the dose was reduced after the application of the Bone algorithm, especially for the application of the Bone algorithm, and the deviation of the mean CT number or Pixel value was measured relatively significantly. In other words, the conditions under which dose was reduced and quality was maintained to reduce the patient's exposure dose and obtain images of the same quality were obtained with the application of the Smooth algorithm and the resulting values of 120 kVp, 160 mA. At this point, doses were reduced by about 28%, and the mean CT number or Pixel value was also measured with relatively little error. If the results are applied to patients who visit the hospital for examination or follow-up after applying various algorithms and follow up scan conditions, the results are considered to be very useful in reducing patient exposure dose.

• Journal of the Korean Society of Radiology
• /
• v.14 no.7
• /
• pp.981-989
• /
• 2020

In this study, a self-made customized phantom was used to quantitatively measure the change in CT number and noise according to the change of pitch. In order to acquire an image using the phantom, the inside of the phantom was filled with sterile distilled water. Inside the glass tube, a solution obtained by diluting the ratio of normal saline and contrast medium to 100%(NS), 400:1, 200:1, 100:1, 50:1, respectively, was placed and imaged. At this time, the pitch was divided into steps of 0, 0.35, 0.7, 1.05, and 1.4 for each dilution ratio of the solution and imaged, respectively. One-way ANOVA analysis were performed to verify whether the mean of the CT number and noise values measured in all ROIs by dilution ratio showed a significant difference according to the change in pitch. As a result of the experiment, there was no statistically significant difference in the change of the CT number according to the change in the pitch for each dilution ratio, but the noise value tended to increase with the increase of the pitch, and showed a statistically significant difference. In the spiral image acquisition of CT, noise can be changed to a significant level depending on the pitch. Therefore, it will be necessary to set the quality evaluation items and criteria for CT images using the spiral image acquisition method.

• Journal of the Korean Society of Radiology
• /
• v.15 no.3
• /
• pp.329-336
• /
• 2021

The Study studied the Inspection Method of Images to obtain a sharp image of the Costume among the bones Composed of Thoracic Using the Thoracic Cage Rando Phantom. At 80 cm of the phantom Distance at the X-ray tube focus, the position of the Phantom was Examined by Changing the Rt and Lt Posterior Oblique(LAO) and Rt and Lt Posterior Postero Oblique positions by 20°, 25° and 30°. The acquired images were Subjectively Evaluated by the Radiographer, and the Evaluation data were analyzed as SPSS ver. 3.0. The signal-to-noise ratio (SNR) was Calculated using the ImageJ Program. As a result, the Cronbach Alpha value was Significantly higher at 0.789. The results of the Signal-to-Noise Ratio (SNR) were high at 20° to 6.038 in the right posterior Transcription Direction at the time of Examination and 7.860, in the Supine Position, for images of Sternum bones. In conclusion, it is Believed that the patient position can be obtained from the Right Anterior Oblique(RAO) Position 20° if the X-ray technique is used to obtain the Sternum's advanced image, and the Left Anterior Oblique(LAO) Position 25° when filming in the Rght lying position.

• Science of Emotion and Sensibility
• /
• v.24 no.4
• /
• pp.129-138
• /
• 2021

This study aimed to determine the effects of the shape and attachment position of stretchable textile sensors coated with carbon nanotube on their performance when used to measure children's joint movements. Moreover, the child-safe requirements for fabric motion sensors are established. The child participants were advised to wear integrated clothing equipped with the sensors of various shapes (rectangular and boat-shaped) and attachment positions (at the knee and elbow joints or 4 cm below the joints). The voltage change induced by the elongation and contraction of the fabric sensors was determined for arm and leg flexion-extension motions at 60 deg/s (three measurements of 10 repeats each for 60°and 90°angles, for a total of 60 repetitions). Their dependability was determined by comparing the fabric motion sensors to the associated acceleration sensors. The experimental results indicate that the rectangular-shaped sensor affixed 4 cm below the joint is the most effective fabric motion sensor for measuring children's arm and leg motions. In this study, we designed a textile sensor capable of tracking children's joint motion and analyzed the sensor shape and attachment position on motion sensing clothing. We demonstrated that flexible fabric sensors integrated into garments may be used to detect the joint motions of the human body.

• Journal of the Korea Society of Computer and Information
• /
• v.27 no.3
• /
• pp.53-61
• /
• 2022

Recent years have drawn a great attention to generation MZ and Metaverse, due to 4th industrial revolution and the development of digital environment that blurs the boundary between reality and virtual reality. Generation MZ approaches the information very differently from the existing generations and uses distinguished communication methods. In terms of learning, they have different motivations, types, skills and build relationships differently. Meanwhile, Metaverse is drawing a great attention as a teaching method that fits traits of gen MZ. Thus, the current research aimed to investigate how to increase the use of Metaverse in Educational Technology. Specifically, this research examined the antecedents of popularity of Gather Town, a platform of Metaverse. Big data of news articles have been collected and analyzed using the Bigkinds system provided by Korea Press Foundation. The analysis revealed, first, a rapid increasing trend of media exposure of Gather Town since July 2021. This suggests a greater utilization of Gather Town in the field of education after the COVID-19 pandemic. Second, Word Association Analysis and Word Cloud Analysis showed high weights on education related words such as 'remote', 'university', and 'freshman', while words like 'Metaverse', 'Metaverse platform', 'Covid19', and 'Avatar' were also emphasized. Third, Network Analysis extracted 'COVID19', 'Avatar', 'University student', 'career', 'YouTube' as keywords. The findings also suggest potential value of Gather Town as an educational tool under COVID19 pandemic. Therefore, this research will contribute to the application and utilization of Gather Town in the field of education.

• Journal of the Korea Convergence Society
• /
• v.13 no.3
• /
• pp.281-289
• /
• 2022

Plasma ozone is utilized in a variety of applications in the field of sterilization due to its high sterilization performance. Dielectric materials used in DBD(dielectric barrier discharges) are mainly polymer, quartz and ceramics. These dielectric layers have the advantage of limiting the amount of supplied electron charge and allowing plasma to occur evenly on the surface of dielectric. Actually, the target or environment for sterilization is often a complex structure, so research and academic study are needed by utilizing the concept of space sterilization. In this study, the device is applied to generate DBD plasma at atmospheric pressure for disinfection due to the effectiveness in producing radicals and ozone. The generator of plasma ozone is a basic structure of dielectric barrier discharge by placing ceramic tube dielectrics and stainless steel electrical conductors at regular intervals. Various applications can be developed based on the proposed design method. Plasma ozone generation for space sterilization device is recognized as an excellent sterilization device. Through the design and verification of the device, we intend to establish an optimal design of the spatial sterilization device and provide the basis data for sterilization applications.

• Journal of the Microelectronics and Packaging Society
• /
• v.30 no.1
• /
• pp.90-94
• /
• 2023

Carbon fiber(CF) with excellent thermal conductivity and electrical conductivity is attracting attention as an alternative material because metal heating elements have problems such as high heat loss and fire risk. However, since CF is oxidized and disconnected at about 200℃ or higher, the application of heating elements is limited, and CF heating elements in the form of vacuum tubes are currently used in some commercial heaters. In this work, polyimide(PI) with high heat resistance was coated on the surface of carbon fiber by electrophoretic deposition to prevent oxidation of CF in the atmosphere without using a vacuum tube, and the coating thickness and heat resistance were investigated according to the applied voltage. The heater made by connecting the PI-coated CF heating elements in series showed stable heating characteristics up to 292℃, which was similar to the heating temperature result of the heat transfer simulation. The PI layer coated by the electrophoretic deposition method is effective in preventing oxidation of CF at 200℃ or higher and is expected to be applicable to various heating components such as secondary batteries, aerospace, and electric vehicles that require heat stability.

• KIPS Transactions on Computer and Communication Systems
• /
• v.12 no.3
• /
• pp.111-118
• /
• 2023

Cyber attacks are increasing worldwide, and attacks on personal privacy such as CCTV and IP camera hacking are also increasing. If you search for IP camera hacking methods in spaces such as YouTube, SNS, and the dark web, you can easily get data and hacking programs are also on sale. If you use an IP camera that has vulnerabilities used by hacking programs, you easily get hacked even if you change your password regularly or use a complex password including special characters, uppercase and lowercase letters, and numbers. Although news and media have raised concerns about the security of IP cameras and suggested measures to prevent damage, hacking incidents continue to occur. In order to prevent such hacking damage, it is necessary to identify the cause of the hacking incident and take concrete measures. First, we analyzed weak account settings and web server vulnerabilities of IP cameras, which are the causes of IP camera hacking, and suggested solutions. In addition, as a specific countermeasure against hacking, it is proposed to add a function to receive a notification when an IP camera is connected and a function to save the connection history. If there is such a function, the fact of damage can be recognized immediately, and important data can be left in arresting criminals. Therefore, in this paper, we propose a method to increase the safety from hacking by using the connection notification function and logging function of the IP camera.