• Advances in environmental research
• /
• v.5 no.4
• /
• pp.263-282
• /
• 2016

Contaminant transport in groundwater induces major threat and harmful effect on the environment; hence, the fate of the contaminant migration in groundwater is seeking a lot of attention. In this paper a two dimensional numerical flow and transport model through saturated layered soil is developed. Groundwater flow and solute transport has been simulated numerically using proposed model. The model implements the finite volume time splitting method to discretize the main equations. The performance, accuracy and efficiency of the out coming numerical models have been successfully examined by two test cases. The verification test cases consist of two-dimensional, groundwater flow and solute transport. The final purpose of this paper is to discuss and compare the shape of contaminant plume in homogeneous and heterogeneous media with different soil properties and control of solute transport using a zone for minimizing the potential of groundwater contamination; furthermore, this model leads to select the effective and optimum remedial strategies for cleaning the contaminated aquifers.

• Korean Journal of Remote Sensing
• /
• v.22 no.5
• /
• pp.445-449
• /
• 2006

Diffuse pollution has been considering as a major source of the quality deterioration of water resources. The establishment of riparian vegetation strips or buffers along those areas of water bodies is used to reduce the threat of diffuse pollution. Remote sensing offers a means by which critical areas could be identified, so that subsequent action toward the establishment of riparian zones can be taken. On the behalf of KOMPSAT-2 satellite imagery as a high resolution spatial data, Landsat TM satellite data are used to aquire the land cover for the riparian buffers studied. This investigation aims to assess the riparian buffers established on the upper Geum river as a pollution mitigation. Through comparing the delineation of riparian buffer zones developed with the existing zones established by the government, we can find the critical distortion points of the existing riparian buffer zone.

• Journal of the Korea Society of Computer and Information
• /
• v.24 no.1
• /
• pp.101-106
• /
• 2019

In this paper, we investigate the patient fall prevention system to prevent the patient from falling out of the bed unintentionally on the bed of the bed. Patients stay in bed for many hours of hospitalization. During the hospitalization period, patients have low controllability of the body, as compared with normal persons, and fall due to intentional movements, resulting in a fall of the patient, can be a fatal threat to the patient. Therefore, an efficient fall prevention system is required. In this paper, the distance map to the patient is generated by the distance measuring sensor on the bed of the patient, and the risk is determined by estimating the position of the patient based on the distance map. As a result, when the distance map of the dangerous area is 150 mm or more, it is determined to be dangerous, and good results are obtained.

• KIPS Transactions on Computer and Communication Systems
• /
• v.4 no.9
• /
• pp.271-282
• /
• 2015

In the business environment BYOD(Bring Your Own Device) is used and being expanded continuously. According to a survey conducted by Cisco in 2012 on 600 companies, 95% of them are already permitting the use of BYOD in their work environments so that productivity of their employees has improved as a result. Gartner predicted that the use of BYOD will be caused new security threat. They also suggested to introduce NAC(Network Access Control) to resolve this threat, to separate network zone based on importance of their business, to establish the policy to consider user authority and device type, and to enforce the policy. The purpose of this paper is to design and implement the NAC for granular access control based on IEEE(Institute of Electrical and Electronics Engineers) 802.1X and DHCP(Dynamic Host Configuration Protocol) fingerprinting, and to analyze the performance on BYOD environment.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.9 no.5
• /
• pp.38-48
• /
• 2010

Adverse weather (e.g. strong winds, snow and ice) will probably appear as a more serious and frequent threat to road traffic than in clear climate. Another consequence of climate change with a natural disastrous on road traffic is respond to traffic accident more the large and high-rise bridge zone, tunnel zone, inclined plane zone and de-icing zone than any other zone, which in turn calls for continuous adaption of monitoring procedures. Accident mitigating measures against this accident category may consist of intense winter maintenance, the use of road weather information systems for data collection and early warnings, road surveillance and traffic control. While hazard from reduced road friction due to snow and ice may be eliminated by snow removal and de-icing measures, the effect of strong winds on road traffic are not easily avoided. The purpose of the study described here, was to design of amber information the relationship between traffic safety, weather, user information on road weather and driving conditions in local-scale Geographic. The most applications are the optimization of the amber information definition, improvements to road surveillance, road weather monitoring and improved accuracy of user information delivery. Also, statistics on wind gust, surface condition, vehicle category and other relevant parameters for wind induced accidents provide basis for traffic control, early warning policies and driver education for improved road safety at bad weather-exposed locations.

• Korean Chemical Engineering Research
• /
• v.61 no.2
• /
• pp.208-216
• /
• 2023

In this study, using the Delphi method, 20 responses to 4 questions (need for launch safety control, top-priority considerations for ensuring public safety during launch, necessary improvements for securing maritime safety, and maritime safety threat factors) regarding launch vehicles and public safety were obtained from experts, and their importance was evaluated to analyze the factors that threaten the reinforcement of maritime safety around launch sites and flight paths when launching. According to the results of an analytic hierarchy process (AHP) analysis, the consistency ratio of the four questions was 4.8%, which is lower than CR ≤ 0.1(10%), and the consistency percentage of the lower measurement indicators was 3.9~5.7%. The derived importance and priority of maritime safety threat factors during launching were in the following order: Substantial human and physical damage in case of launch accidents(0.36), Prepare legal bases (e.g., penalty details) regarding maritime control(0.32), Secure the safety of personnel, equipment, and facilities in danger zone(0.31), Unauthorized entry of vessels in maritime control zones and non-compliance to restrictions(0.30). This article can serve as a reference for strengthening maritime safety in areas around launch sites and flight paths.

• Strategy21
• /
• s.33
• /
• pp.37-64
• /
• 2014

The year 2010 has been regarded as a year of China's assertive diplomacy. A series of China's behavior--including China's critical reaction to the U.S. for its sales of weapons to Taiwan, the Dalai Lama's visit to President Obama, China's arbitrary designation of 'core interests' over the South China Sea, China's inordinate reactions to the sinking of the Cheonan and Yeonpyeong bombardment, and China's activities in the Senkaku/Diaoyu island areas--has served as the witnesses to China's assertive diplomacy in 2010. The major causes of China's assertive diplomacy can be summed up by three factors: potential power transition from U.S. to China; emerging China's nationalism; and the recession of the Tao Guang Yang Hui as a diplomatic principle. But a majority of Western sinologists claim that China's assertive diplomacy is defensive in terms of its character. China's neighboring states, however, perceive its assertive diplomacy as diplomatic threat. Due to these states' geographical proximity and capability gaps with China, these neighbors experience difficulties in coping with China's behavior. In particular, China's coercive economic diplomacy, in which China tends to manipulate the neighbors' economic dependency on China for its diplomatic leverage, is a case in point for China's assertive diplomacy. China's assertiveness seems to be continued even after the inauguration of Xi Jinping government. Although the Xi government's diplomatic rhetorics in "New Type of Great Power Relationship" and the "Convention for Neighboring States Policy" sound friendly and cooperative, its subsequent behavior, like unilateral announcement of Chinese Air Defense Identification Zone (CADIZ), does not conform with its rhetoric. Overall, China's assertiveness has been consolidated as a fashion of its diplomacy, and it is likely to continue in its relations with neighbors. As a neighboring state, the ROK should approach to it with more balanced attitude. In addition, it needs to find out a new diplomatic leverage to deal with China in accordance with its security environment, in which China plays a growing role.

• Journal of Soil and Groundwater Environment
• /
• v.25 no.3
• /
• pp.43-51
• /
• 2020

About 90% of groundwater wells in Jeju Island are reported to be under the threat of contamination by infiltration of the surface pollutants. Most of those wells have improperly grouted annulus which is an empty space between the well and the inner casing. As a remedy to this problem, some of the wells were re-grouted by filling the annulus with cement without lifting an inner casing. In order to evaluate whether this method is appropriate for the geological structure of Jeju Island, two wells (W1 and W2) were selected and this method was applied. The water holding capacity did not decrease while the nitrate levels decreased from 16.8 and 20.2 to 6.8 and 13.8 mg/L in W1 and W2, respectively. The higher nitrate level in W2 is deemed to be influenced by the livestock farms located in the upper area of the well. In addition, transmissivity of the vedose zone was higher in W2 than W1, potentially facilitating the transport of nitrate to the groundwater. The overall result of this study suggests re-grouting of wells for the purpose of protecting water quality of goundwater should take into account geological structure of vadose zone as well as appropriate source control of the contaminants.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.23 no.6
• /
• pp.1069-1086
• /
• 2013

Nowadays, web defacement becomes the utmost threat which can harm the target organization's image and reputation. These defacement activities reflect the hacker's political motivation or his tendency. Therefore, the analysis of the hacker's activities can give the decisive clue to pursue criminals. A specific message or photo or music on the defaced web site and the outcome of analysis will be supplying some decisive clues to track down criminals. The encoding method or used fonts of the remained hacker's messages, and hacker's SNS ID such as Twitter or Facebook ID also can help for tracking hackers information. In this paper, we implemented the web defacement analysis system by applying CBR algorithm. The implemented system extracts the features from the web defacement cases on zone-h.org. This paper will be useful to understand the hacker's purpose and to plan countermeasures as a IDSS(Investigation Detection Support System).

• Journal of Aerospace System Engineering
• /
• v.11 no.2
• /
• pp.35-42
• /
• 2017

This paper analyzes the intention of the PRC (People's Republic of China) to establish and operate CADIZ to implement the government's maritime policy and strategy and to project its air power in preparation for maritime provocation and contingency, especially over the area where East Asia countries have claimed to have maritime jurisdiction over one another. This paper is also intended to guide the Republic of Korea's response measures for coping with the maritime intention and threat of China by such measures as reinforcing military power, constructing the strategic air base in Jeju, and expanding the present KADIZ.