• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.10 no.2
• /
• pp.857-880
• /
• 2016

Due to an increasing number of cyberattacks globally, cybersecurity has become a crucial part of national security in many countries. In particular, the Digital Pearl Harbor has become a real and aggressive security threat, and is considered to be a global issue that can introduce instability to the dynamics of international security. Against this context, the cyberattacks that targeted nuclear power plants (NPPs) in the Republic of Korea triggered concerns regarding the potential effects of cyber terror on critical infrastructure protection (CIP), making it a new security threat to society. Thus, in an attempt to establish measures that strengthen CIP from a cybersecurity perspective, we perform a case study on the cyber-terror attacks that targeted the Korea Hydro & Nuclear Power Co., Ltd. In order to fully appreciate the actual effects of cyber threats on critical infrastructure (CI), and to determine the challenges faced when responding to these threats, we examine factual relationships between the cyberattacks and their responses, and we perform analyses of the characteristics of the cyberattack under consideration. Moreover, we examine the significance of the event considering international norms, while applying the Tallinn Manual. Based on our analyses, we discuss implications for the cybersecurity of CI in South Korea, after which we propose a framework for strengthening cybersecurity in order to protect CI. Then, we discuss the direction of national policies.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.32 no.2
• /
• pp.157-160
• /
• 2006

Nasotracheal intubation is performed routinely in maxillofacial surgery to optimize visualization of the surgical field. The CaldwellLuc operation is an approach to the maxillary sinus through the labiogingival sulcus and canine fossa. The operation is used to treat chronic maxillary sinusitis, and involves curettage of the mucosa of the maxillary sinus and the creation of an inferior meatal antrostomy. After the operation, a nasal Foley catheter is inserted into the inferior nasal meatus for the discharge of blood and tissue fluid. Then, the nostril is packed with vaseline gauze. Before the patients awaken, they experience impaired switching from nasal to oral breathing. Pulmonary edema can result from excessive negative intrathoracic pressure caused by acute airway obstruction in patients breathing spontaneously. During anesthesia and sedation, airway obstruction can occur at the levels of the pharynx and larynx. Even in patients who are awake, alteration in the ability to change the breathing route from nasal to oral may affect breathing in the presence of an airway obstruction, causing this catastrophic event. We experienced a case in which acute pulmonary edema resulted from acute airway obstruction triggered by the patient's inability to switch the breathing route from nasal to oral during emergence from anesthesia.

• Parasites, Hosts and Diseases
• /
• v.54 no.5
• /
• pp.679-684
• /
• 2016

Clonorchiasis, caused by direct contact with Clonorchis sinensis worms and their excretory-secretory products (ESPs), is associated with chronic inflammation, malignant changes in bile ducts, and even cholangiocarcinogenesis. Our previous report revealed that intracellular free radicals enzymatically generated by C. sinensis ESPs cause NF-${\kappa}B$-mediated inflammation in human cholangiocarcinoma cells (HuCCT1). Therefore, the present study was conducted to examine the role of upstream Toll-like receptors (TLRs) on the initial host innate immune responses to infection. We found that treatment of HuCCT1 cells with native ESPs induced changes in TLR mRNA levels in a time-dependent manner, concomitant with the generation of free radicals. ESP-mediated free radical generation was markedly attenuated by preincubation of the cells with TLR1-4-neutralizing antibodies, indicating that at least TLR1 through 4 participate in stimulation of the host innate immune responses. These findings indicate that free radicals triggered by ESPs are critically involved in TLR signal transduction. Continuous signaling by this pathway may function in initiating C. sinensis infection-associated inflammation cascades, a detrimental event leading to progression to more severe hepatobiliary diseases.

• Computers and Concrete
• /
• v.33 no.5
• /
• pp.545-557
• /
• 2024

A real-case incident occurred where a 9-meter-high segment of a pre-fabricated concrete separation wall unexpectedly collapsed. This collapse was triggered by improperly depositing excavated soil against the wall's back, a condition for which the wall segments were not designed to withstand lateral earth pressure, leading to a flexural failure. The event's analysis, integrating technical data and observational insights, revealed that internal forces at the time of failure significantly exceeded the wall's capacity per standard design. The Lattice Discrete Particle Model (LDPM) further replicates the collapse mechanism. Our approach involved defining various parameter sets to replicate the concrete's mechanical response, consistent with the tested compressive strength. Subsequent stages included calibrating these parameters across different scales and conducting full-scale simulations. These simulations carried out with various parameter sets, were thoroughly analyzed to identify the most representative failure mechanism. We developed an equation from this analysis that quickly correlates the parameters to the wall's load-carry capacity, aligned with the simulation. Additionally, our study examined the wall's post-peak behavior, extending up to the point of collapse. This aspect of the analysis was essential for preventing failure, providing crucial time for intervention, and potentially averting a disaster. However, the reinforced concrete residual state is far from being fully understood. While it's impractical for engineers to depend on the residual state of structural elements during the design phase, comprehending this state is essential for effective response and mitigation strategies after initial failure occurs.

• Molecules and Cells
• /
• v.39 no.5
• /
• pp.426-438
• /
• 2016

Plant disease resistance occurs as a hypersensitive response (HR) at the site of attempted pathogen invasion. This specific event is initiated in response to recognition of pathogen-associated molecular pattern (PAMP) and subsequent PAMP-triggered immunity (PTI) and effector-triggered immunity (ETI). Both PTI and ETI mechanisms are tightly connected with reactive oxygen species (ROS) production and disease resistance that involves distinct biphasic ROS production as one of its pivotal plant immune responses. This unique oxidative burst is strongly dependent on the resistant cultivars because a monophasic ROS burst is a hallmark of the susceptible cultivars. However, the cause of the differential ROS burst remains unknown. In the study here, we revealed the plausible underlying mechanism of the differential ROS burst through functional understanding of the Magnaporthe oryzae (M. oryzae) AVR effector, AVR-Pii. We performed yeast two-hybrid (Y2H) screening using AVR-Pii as bait and isolated rice NADP-malic enzyme2 (Os-NADP-ME2) as the rice target protein. To our surprise, deletion of the rice Os-NADP-ME2 gene in a resistant rice cultivar disrupted innate immunity against the rice blast fungus. Malic enzyme activity and inhibition studies demonstrated that AVR-Pii proteins specifically inhibit in vitro NADP-ME activity. Overall, we demonstrate that rice blast fungus, M. oryzae attenuates the host ROS burst via AVR-Pii-mediated inhibition of Os-NADP-ME2, which is indispensable in ROS metabolism for the innate immunity of rice. This characterization of the regulation of the host oxidative burst will help to elucidate how the products of AVR genes function associated with virulence of the pathogen.

• Asian Pacific Journal of Cancer Prevention
• /
• v.15 no.11
• /
• pp.4519-4525
• /
• 2014

Oleanolic acid (OA) is a nutritional component widely distributed in various vegetables. Although it has been well recognized for decades that OA exerts certain anti-tumor activity by inducing mitochondria-dependent apoptosis, it is still unclear that what molecular signaling is responsible for this effect. In this study, we employed cancer cell lines, A549, BXPC-3, PANC-1 and U2OS to elucidate the molecular mechanisms underlying OA anti-tumor activity. We found that activation of MAPK pathways, including p-38 MAPK, JNK and ERK, was triggered by OA in both a dose and time-dependent fashion in all the tested cancer cells. Activation was accompanied by cleavage of caspases and PARP as well as cytochrome C release. SB203580 (p38 MAPK inhibitor), but not SP600125 (JNK inhibitor) and U0126 (ERK inhibitor), rescued the pro-apoptotic effect of OA on A549 and BXPC-3 cells. OA induced p38 MAPK activation promoted mitochondrial translocation of Bax and Bim, and inhibited Bcl-2 function by enhancing their phosphorylation. OA can induce reactive oxygen species (ROS)-dependent ASK1 activation, and this event was indispensable for p38 MAPK-dependent apoptosis in cancer cells. In vivo, p38 MAPK knockdown A549 tumors proved resistant to the growth-inhibitory effect of OA. Collectively, we elucidated that activation of ROS/ASK1/p38 MAPK pathways is responsible for the apoptosis stimulated by OA in cancer cells. Our finding can contribute to a better understanding of molecular mechanisms underlying the antitumor activity of nutritional components.

• Geophysics and Geophysical Exploration
• /
• v.13 no.3
• /
• pp.295-300
• /
• 2010

Recently, many tsunamis triggered by impulsive undersea ground motions occurred in subduction zones around the Pacific Ocean area including the East Sea surrounded by Korea, Japan and Russia. The wave height of a tsunami may be in the order of several meters, while the wavelength can be up to 1,000 km in the ocean, where the average water depth is about 4 km. A tsunami could cause a severe coastal flooding and property damage not only at neighboring countries but also at distant countries. A fundamental and economic way to mitigate unusual tsunami attacks is to construct tsunami hazard maps along coastal areas vulnerable to tsunami flooding. These maps should be developed based on the historical tsunami events and projected scenarios. The map could be used to make evacuation plans in the event of a real tsunami assault.

• Journal of the Korean Society of Hazard Mitigation
• /
• v.10 no.3
• /
• pp.147-154
• /
• 2010

This study analyzed the characteristics of sediment produce by landslide triggered by rainfall. One-dimensional unsaturated groundwater model and infinite slope stability analysis were used to estimate the behavior of soil moisture and slope stability according to rainfall, respectively. Slope stability analysis was performed considering on soil depth and characteristics of trees. The results of the analysis on characteristics of sediment produce according to rainfall events showed that the sediment produce by landslide was mainly contributed to rainfall intensity and its temporal clustering. The results of the analysis on characteristics of sediment produce by extreme events showed that remaining rainfall amount of typhoon 'Rusa' was much more than that of the other extreme events, and thus this remaining rainfall was to contribute to sediment transportation. Additionally, only a small number of extreme events were found to cause most amount of sediment produce in a basin.

• Journal of The Korean Astronomical Society
• /
• v.41 no.6
• /
• pp.173-180
• /
• 2008

Using the MHD coronal seismology technique, we estimated the magnetic field for three spicules observed in 2008 June. For this study, we used the high resolution Ca II H line ($3968.5\;{\AA}$) images observed by the Hinode SOT and considered a vertical thin flux tube as a spicule model. To our knowledge, this is the first attempt to estimate the spicule magnetic field using the Hinode observation. From the observed oscillation properties, we determined the periods, amplitudes, minimum wavelengths, and wave speeds. We interpreted the observed oscillations as MHD kink waves propagating through a vertical thin flux tube embedded in a uniform field environment. Then we estimated spicule magnetic field assuming spicule densities. Major results from this study are as follows : (1) we observed three oscillating spicules having durations of 5-7 minutes, oscillating periods of 2-3 minutes, and transverse displacements of 700-1000 km. (2) The estimated magnetic field in spicules is about 10-18 G for lower density limit and about 43-76 G for upper density limit. (3) In this analysis, we can estimate the minimum wavelength of the oscillations, such as 60000 km, 56000 km, and 45000 km. This may be due to the much longer wavelength comparing with the height of spicules. (4) In the first event occurred on 2008 June 03, the oscillation existed during limited time (about 250 s). This means that the oscillation may be triggered by an impulsive mechanism (like low atmospheric reconnection), not continuous. Being compared with the ground-based observations of spicule oscillations, our observation indicates quite different one, i.e., more than one order longer in wavelength, a factor of 3-4 larger in wave speed, and 2-3 times longer in period.

• The Korean Journal of Applied Statistics
• /
• v.20 no.1
• /
• pp.1-9
• /
• 2007

This investigation on the change of the daily maxima temperature in Seoul, Daegu, Chunchen, Youngchen was triggered by news items such as the earth is getting warmer and a recent news item that said that Korea is getting warmer due to this climatic change. A statistical analysis on the daily maxima for June over this period in Seoul revealed a positive trend of 1.1190 centigrade over the 45 years, a change of 0.0249 degrees annually. Due to the large variation on these maximum temperatures, one can raise the question on the significance of this increase. To check the goodness of fit of the proposed extreme value model, we shown a Q-Q plot of the observed quantiles against the simulated quantiles and a probability plot. And we calculated statistics each month and a tolerance limit. This is tested through simulating a large number of similar datasets from an Extreme Value distribution which described the observed data very well. Only 0.02% of the simulated datasets showed an increase of this degrees or larger, meaning that the probability is very low for such an event to occur.