• Journal of Internet Computing and Services
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• v.22 no.6
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• pp.33-40
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• 2021

Automatic Speech Recognition(ASR) is a technology that analyzes human speech sound into speech signals and then automatically converts them into character strings that can be understandable by human. Speech recognition technology has evolved from the basic level of recognizing a single word to the advanced level of recognizing sentences consisting of multiple words. In real-time voice conversation, the high recognition rate improves the convenience of natural information delivery and expands the scope of voice-based applications. On the other hand, with the active application of speech recognition technology, concerns about related cyber attacks and threats are also increasing. According to the existing studies, researches on the technology development itself, such as the design of the Automatic Speaker Verification(ASV) technique and improvement of accuracy, are being actively conducted. However, there are not many analysis studies of attacks and threats in depth and variety. In this study, we propose a cyber attack model that bypasses voice authentication by simply manipulating voice frequency and voice speed for AI voice recognition service equipped with automated identification technology and analyze cyber threats by conducting extensive experiments on the automated identification system of commercial smartphones. Through this, we intend to inform the seriousness of the related cyber threats and raise interests in research on effective countermeasures.

• Journal of the Institute of Convergence Signal Processing
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• v.23 no.4
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• pp.194-199
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• 2022

Preprocessing for high-quality data is required for high accuracy and usability in various and complex image data-based industries. However, when a contaminated hostile example that combines noise with existing image or video data is introduced, which can pose a great risk to the company, it is necessary to restore the previous damage to ensure the company's reliability, security, and complete results. As a countermeasure for this, restoration was previously performed using Defense-GAN, but there were disadvantages such as long learning time and low quality of the restoration. In order to improve this, this paper proposes a method using adversarial examples created through FGSM according to image segmentation in addition to using the VQ-VAE model. First, the generated examples are classified as a general classifier. Next, the unsegmented data is put into the pre-trained VQ-VAE model, restored, and then classified with a classifier. Finally, the data divided into quadrants is put into the 4-split-VQ-VAE model, the reconstructed fragments are combined, and then put into the classifier. Finally, after comparing the restored results and accuracy, the performance is analyzed according to the order of combining the two models according to whether or not they are split.

• Journal of Korean Neurosurgical Society
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• v.65 no.3
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• pp.422-429
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• 2022

Objective : Extracranial supra-aortic dissections (ESADs) with severe stenosis, occlusion and/or pseudoaneurysm presents potential risk of stroke. Endovascular stenting to reconstruct non acute phase ESADs (NAP-ESADs) is an alternative to anticoagulant or antiplatelet therapy. However, its feasibility, safety and efficacy of stenting in NAP-ESADs is unclear. This study aims to investigate the long-term outcomes of the feasibility, safety and efficacy of stenting in NAP-ESADs. Methods : Seventy-four patients with 91 NAP-ESAD vessels with severe stenosis, occlusion and/or pseudoaneurysm presents potential risk of stroke who underwent stent remodeling were enrolled into this respective study from December 2008 to March 2020. Technical success rate, complications, clinical and angiographic results were harvested and analyzed. Results : Success rate of stent deployment was 99% (90/91) with no procedural mortality or morbidity. Transient ischemic attack occurred in three patients during operation (4.1%, 3/74). Asymptomatic embolisms of distal intracranial vessels were found in two patients (2.7%, 2/74). One hundred and forty-two stents deployed at 85 carotid (135 stents) and six vertebral (seven stents) vessels. Six stent types (Wingspan, 28/135, 20.7%; Solitaire, 10/135, 7.4%; Neuroform, 8/135, 5.9%; LVIS, 2/135, 1.5%; Precise, 75/135, 55.6%; Acculink, 12/135, 8.9%) were deployed at carotid arterial dissection while two types (Wingspan, 5/7, 71.4%; Solitaire 2/7, 28.6%) at vertebral arterial dissection. Digital subtracted angiography (56%, 51/91), computational tomography angiography (41.8%, 38/91) and high resolution magnetic resonance imaging (2.2%, 2/91) were adopted for follow up, with a mean time of 17.2±15.4 months (5-77). All patient modified Rankin Scale scores showed no increase at discharge or follow-up. Angiographically, dissections in 86 vessels in 69 patients (94.5%, 86/91) were completely reconstructed with only minor remnant dissections in four vessels in four patients (4.4%, 4/91). Severe re-stenosis in the stented segment required re-stenting in one patient (1.1%, 1/91). Conclusion : Stent remodeling technique provides feasible, safe and efficacious treatment of ESADs patients with severe stenosis, occlusion and/or pseudoaneurysm.

• Korean Journal of Artificial Intelligence
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• v.11 no.2
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• pp.39-44
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• 2023

The creativity of thesis is that the significance of cyber security challenges in blockchain. The variety of enterprises, including those in the medical market, are the targets of cyberattacks. Hospitals and clinics are only two examples of medical facilities that are easy targets for cybercriminals, along with IoT-based medical devices like pacemakers. Cyberattacks in the medical field not only put patients' lives in danger but also have the potential to expose private and sensitive information. Reviewing and looking at the present and historical flaws and vulnerabilities in the blockchain-based IoT and medical institutions' equipment is crucial as they are sensitive, relevant, and of a medical character. This study aims to investigate recent and current weaknesses in medical equipment, of blockchain-based IoT, and institutions. Medical security systems are becoming increasingly crucial in blockchain-based IoT medical devices and digital adoption more broadly. It is gaining importance as a standalone medical device. Currently the use of software in medical market is growing exponentially and many countries have already set guidelines for quality control. The achievements of the thesis are medical equipment of blockchain-based IoT no longer exist in a vacuum, thanks to technical improvements and the emergence of electronic health records (EHRs). Increased EHR use among providers, as well as the demand for integration and connection technologies to improve clinical workflow, patient care solutions, and overall hospital operations, will fuel significant growth in the blockchain-based IoT market for linked medical devices. The need for blockchain technology and IoT-based medical device to enhance their health IT infrastructure and design and development techniques will only get louder in the future. Blockchain technology will be essential in the future of cybersecurity, because blockchain technology can be significantly improved with the cybersecurity adoption of IoT devices, i.e., via remote monitoring, reducing waiting time for emergency rooms, track assets, etc. This paper sheds the light on the benefits of the blockchain-based IoT market.

• Maritime Security
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• v.6 no.1
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• pp.1-35
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• 2023

The purpose of this study is to present the direction of development of our navy's response strategy through analysis at the ends, ways, and means level of the Chinese navy's offensive strategy for the West Sea. As a result of the analysis, at the ends level, the Chinese Navy's offensive strategy for the West Sea strategy is being linked to a grand strategy to protect maritime rights and achieve maritime power between the U.S. and China competition, at the ways level, the Chinese Navy is expected to create a foundation for the international community to recognize the West Sea as China's inland sea through "routine entry" and "exercise authority", and in case of emergency, it will try to secure sea control in the West Sea in a short period of time by blocking Korea's maritime transportation route based on the overwhelming preemptive attack capability of aircraft carriers. At the means level, it is accelerating the construction of aircraft carrier warfare units and improving its ability to engage long-range missiles. As a direction of development of the Korean Navy's response strategy in response to this, first, Establishment and Development of National Maritime Security Strategy in conjunction with the Korean Indo-Pacific Strategy. Second, it proposes the development of the concept of effective security operations for the east sea area of the West Sea intermediate line, and third, the development of the concept of combat performance and capacity building to strengthen survival and lethality.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.5B
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• pp.547-558
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• 2008

With the advent of super cargo ship due to the explosive increase in the amount of cargo shipped via seas, some mega ports are under construction in South Korea, to accommodate the super cargo ship, and some of them already enter their final phase. To sustain the harbor tranquility, mega ports usually comprise huge vertical type breakwaters which are intrinsically vulnerable to the attack of long waves. In this rationale, we present the chamber type breakwater with a circular curtain wall - Eco-breaker 2, to alleviate the reflection of long waves and numerically investigate the hydraulic characteristics of Eco-breaker 2. As a wave driver, we use the Navier-Stokes eq., the most robust wave driver, using SPH (Smoothed Particle Hydrodynamics) and LES (Large Eddy Simulation). For the verification of numerical results, we also carried out hydraulic model test. It is shown that Eco-breaker 2 can effectively alleviate the reflection of long waves with its inherited large organized eddies encompassing the water chamber and some region off the curtain wall of varying size. It is also shown that the scope and strength of large organized eddies strongly depends on the incident wave period, and the reflection coefficient can be lowered to 0.18 by tuning the size of water chamber such that resident time at the chamber is just short of the half period of incident waves. Based on these results, we present the specification of Eco-breaker 2 to boost its use on the development of water environment friendly harbor worldwide.

• 한국노년학
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• v.39 no.3
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• pp.485-515
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• 2019

The purpose of this study was to explore bullying among senior women at a senior center. Using ethnographic research technique, we examined the process in which members of the senior center engaged in and responded to bullying. Purposive sampling method was used to choose a senior center as the subject of this study. Within the center, 16 senior women participated in the study. In-depth interviews and participatory research methods were used to collect data. We analyzed the transcripts of the interviews based on the ethnographic analysis method presented by Spradley (1979). Themes that emerged from these participatory research and interviews include: members of the senior center creating loners, people being bullied causing damages to the group, taking actions to respond to bullying, and failing to solve the bullying problems. First, the victims of bullying became loners with no one to rely on through other members' verbal attacks, discrimination, isolation, and stopping the victim to use the senior center. Second, the victims were under attack but also caused troubles at the senior center and harmed others at the same time. Third, while engaging in bullying, senior women attempted to deal with bullying problems in many ways. These attempts include: avoiding the conflict, withstanding, attempting to mediating, and so on. Finally, bullying remained to be a recurring phenomenon at the senior center. New victims of bullying continuously appeared and the influence of bullying was felt not only within the senior center but outside as well. Based on the findings of this study, we suggest that practitioners and researchers take into account factors that affect bullying among senior women.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.34 no.2
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• pp.263-279
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• 2024

With the increasing trend of Cloud migration, security threats in the Cloud computing environment have also experienced a significant increase. Consequently, the importance of efficient incident investigation through log data analysis is being emphasized. In Cloud environments, the diversity of services and ease of resource creation generate a large volume of log data. Difficulties remain in determining which events to investigate when an incident occurs, and examining all the extensive log data requires considerable time and effort. Therefore, a systematic approach for efficient data investigation is necessary. CloudTrail, the Amazon Web Services(AWS) logging service, collects logs of all API call events occurring in an account. However, CloudTrail lacks insights into which logs to analyze in the event of an incident. This paper proposes an automated analysis framework that integrates Cloud Matrix and event information for efficient incident investigation. The framework enables simultaneous examination of user behavior log events, event frequency, and attack information. We believe the proposed framework contributes to Cloud incident investigations by efficiently identifying critical events based on the ATT&CK Framework.

• Journal of Korean Society of Environmental Engineers
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• v.38 no.12
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• pp.647-655
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• 2016

Lead dioxide ($PbO_2$) is an electrode material that is effective for organic pollutant degradation based on hydroxyl radical ($^{\bullet}OH$) attack. Representative parameters for $PbO_2$ electrodeposition are summarized to current, temperature, reaction time, concentration of Pb(II) and electrolyte agent. In this study, $Ti/PbO_2$ electrodes were fabricated by electrodeposition method under controlled reaction time, current density, temperature, concentration of $HNO_3$ electrolyte. Effects of deposition parameters on $^{\bullet}OH$ evolution were investigated in terms of electrochemical bleaching of p-Nitrosodimethylaniline (RNO). As major results, the $^{\bullet}OH$ evolution was promoted at the $PbO_2$ that was deposited in longer reaction time (1-90 min), lower current density ($0.5-50mA/cm^2$), higher temperature ($5-65^{\circ}C$) and lower $HNO_3$ concentration (0.01-1.0 M). Especially, the $PbO_2$ which was deposited in 0.01 M of lowest $HNO_3$ concentration by applying $20mA/cm^2$ for above 10 min was most effective on $^{\bullet}OH$ evolution. The performance gap between $PbO_2$s that was best and worst in $^{\bullet}OH$ evolution was about 41%. Among the properties of $PbO_2$ related on $^{\bullet}OH$ evolution performance, conductivity of $Ti/PbO_2$ significantly influenced on $^{\bullet}OH$ evolution. The increase in conductivity promoted $^{\bullet}OH$ evolution. In addition, the increase in crystal size of $PbO_2$ interfered $^{\bullet}OH$ evolution at surface of some $PbO_2$ deposits.

• Journal of Korean Orthopaedic Sports Medicine
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• v.5 no.1
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• pp.69-74
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• 2006

Purpose: To perform the retrospective analysis of the sports injuries sustained by the college Taekwondo athletes in the respect of the injury patterns, mechanism of injury and clinical outcome Materials and Methods: This study is based on 47 out of 49 college Takwondo athletes, who had experienced the Takwondo related musculoskeletal injuries severe enough to visit the clinic for medical treatment. The mean age at the time of injury was 18.8 years and 39 were males and 8 females. The Taekwondo career was average 9.6 years and the injuries were sustained at average 6.7 years of their career. The injuries were analyzed by the detailed interview with thorough physical examination. Results: Forty-seven Taekwondo athletes in the study experienced average 1.8 injury/person (total 85 cases) with 26 persons of one time experience(55.3%), 11 persons of 2 times(23.4%),4 persons of 3 times (8.5%),5 persons of 4 times (10.6%) and 1 person of 5 times (2.2%). Injuries occurred during training in 50 cases (58.8%), while during match in 35 cases (41.2%). Injuries occurred during the attack phase of the match are 26 cases (31.7%) while 49 cases (57.6%) during the defense phase. As for the pattern of injury, fracture was the most common with 49 cases (57.6%), followed by ligament injury with 21 cases (24.7%). The upper extremity injuries were 32 cases (37.7%) while the lower extremity injuries were 44 cases (51.8%) Mode of medical treatment were operation in 15cases(17.7%), cast in 21 cases(24.7%), splint in 33 cases (38.8%), physical therapy in 15cases(17.7%) and acupuncture in 1 case(1.1%) Conclusion: Almost all the college Taekwondo athletes (96%) experienced sports injuries severe enough to receive medical treatments with the fracture being the most common injury pattern. The injuries occurred more commonly during the defense phase of the competition.