• Journal of the Korean Society of Marine Environment & Safety
• /
• v.25 no.2
• /
• pp.178-188
• /
• 2019

When using a distributed system, it is very important to know the intention of a target ship in order to prevent collisions. The action taken by a certain ship for collision avoidance and the action of the target ship it intends to avoid influence each other. However, it is difficult to establish a collision avoidance plan in consideration of multiple-ship situations for this reason. To solve this problem, a Distributed Stochastic Search Algorithm (DSSA) has been proposed. A DSSA searches for a course that can most reduce cost through repeated information exchange with target ships, and then indicates whether the current course should be maintained or a new course should be chosen according to probability and constraints. However, it has not been proven how the parameters used in DSSA affect collision avoidance actions. Therefore, in this paper, I have investigated the effect of the parameters and weight factors of DSSA. Experiments were conducted by combining parameters (time window, safe domain, detection range) and weight factors for encounters of two ships in head-on, crossing, and overtaking situations. A total of 24,000 experiments were conducted: 8,000 iterations for each situation. As a result, no collision occurred in any experiment conducted using DSSA. Costs have been shown to increase if a ship gives a large weight to its destination, i.e., takes selfish behavior. The more lasting the expected position of the target ship, the smaller the sailing distance and the number of message exchanges. The larger the detection range, the safer the interaction.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.25 no.5
• /
• pp.527-534
• /
• 2019

Several types of mathematical analysis methods are used for port waterway risk assessment based on marine traffic volume. In Korea, a marine traffic congestion model that standardizes the size of the vessels passing through the port waterway is applied to evaluate the risk of the waterway. For example, when marine traffic congestion is high, risk situations such as collisions are likely to occur. However, a scientific review is required to determine if there is a correlation between high density of maritime traffic and a high risk of waterway incidents. In this study, IWRAP Mk2(IALA official recommendation evaluation model) and a marine traffic congestion model were used to analyze the correlation between port waterway risk and marine traffic congestion in the same area. As a result, the linear function of R2 was calculated as 0.943 and it was determined to be significant. The Pearson correlation coefficient was calculated as 0.971, indicating a strong positive correlation. It was confirmed that the port waterway risk and the marine traffic congestion have a strong correlation due to the influence of the common input variables of each model. It is expected that these results will be used in the development of advanced models for the prediction of port waterway risk assessment.

• Journal of Korean Neurosurgical Society
• /
• v.62 no.4
• /
• pp.376-381
• /
• 2019

Objective : To define optimal method that calculate the safe direction of cervical pedicle screw placement using computed tomography (CT) image based three dimensional (3D) cortical shell model of human cervical spine. Methods : Cortical shell model of cervical spine from C3 to C6 was made after segmentation of in vivo CT image data of 44 volunteers. Three dimensional Cartesian coordinate of all points constituting surface of whole vertebra, bilateral pedicle and posterior wall were acquired. The ideal trajectory of pedicle screw insertion was defined as viewing direction at which the inner area of pedicle become largest when we see through the biconcave tubular pedicle. The ideal trajectory of 352 pedicles (eight pedicles for each of 44 subjects) were calculated using custom made program and were changed from global coordinate to local coordinate according to the three dimensional position of posterior wall of each vertebral body. The transverse and sagittal angle of trajectory were defined as the angle between ideal trajectory line and perpendicular line of posterior wall in the horizontal and sagittal plane. The averages and standard deviations of all measurements were calculated. Results : The average transverse angles were $50.60^{\circ}{\pm}6.22^{\circ}$ at C3, $51.42^{\circ}{\pm}7.44^{\circ}$ at C4, $47.79^{\circ}{\pm}7.61^{\circ}$ at C5, and $41.24^{\circ}{\pm}7.76^{\circ}$ at C6. The transverse angle becomes more steep from C3 to C6. The mean sagittal angles were $9.72^{\circ}{\pm}6.73^{\circ}$ downward at C3, $5.09^{\circ}{\pm}6.39^{\circ}$ downward at C4, $0.08^{\circ}{\pm}6.06^{\circ}$ downward at C5, and $1.67^{\circ}{\pm}6.06^{\circ}$ upward at C6. The sagittal angle changes from caudad to cephalad from C3 to C6. Conclusion : The absolute values of transverse and sagittal angle in our study were not same but the trend of changes were similar to previous studies. Because we know 3D address of all points constituting cortical shell of cervical vertebrae. we can easily reconstruct 3D model and manage it freely using computer program. More creative measurement of morphological characteristics could be carried out than direct inspection of raw bone. Furthermore this concept of measurement could be used for the computing program of automated robotic screw insertion.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.20 no.7
• /
• pp.474-484
• /
• 2019

In this age, where the social environment is changing rapidly and unpredictably, interest in safety from crime is increasing in Korean society. As the desire to live a life free from the fear of crime increases, interest in the construction of safe cities is also rising nationwide. To meet the national demand, the Korean government is promoting a project to link public disaster safety systems by involving municipalities, 112, 119, and other emergency services and institutions through the Smart City Integrated Platform in order to construct a smart safety net. This study investigates the linking of theSmart City Integrated Platform and theIntelligent Security Project. The results are as follows. 1. The linkage's objective is clear. 2. The system sector can provide information to accident-related organizations. 3. The scenario area can be expanded to a crime-prevention sector, and a long-term urban information integration infrastructure can be created. 4. Product testing is enabled by a smart city road map and through continuous consultation with relevant organizations. 5. Project diffusion to other local governments can be promoted with the continued addition of commercial products.

• Journal of the Korean Institute of Rural Architecture
• /
• v.21 no.2
• /
• pp.19-26
• /
• 2019

Pungsu theory is important one in the site selection and lay-out of traditional Korean village and house. In this aspect, Study with a view of Pungsu theory might be used as a proper method for understanding the traditional architecture in Korea. In this context, this study analyzes the Jeong, Dong-Ho's house which is designated no. 19 as an important folk cultural heritage, located in Jigok Ochu-gil 133-62, Godeok-myon, Yesan-gun, Chungnam province. The analysis of the site and space lay-out is carried out by Yong(Dragon), Hyoel(Auspicious Spot), Sa(Sands), Su(Water) aspects of the Pungsu(Fengshui) Hyungsei-ron. The house is depending upon soft dragon vein connecting with a earth type rear mountain. It looks southeast direction, Gonjwasonhyang(乾坐巽向). The hyeolseong(穴星) has classical venus shape, and there is no faults relatively. The Sasinsa condition is almost perfect that right blue dragon and left white tiger surround the hyeol with 3-4 layers and the facing mountain covers the front open area. The water flowing from inside of left and right mountain is joined in front of the house so it could stop flowing out of vital energy. Bibo forest(裨補樹) is placed properly to protect the easy disclose of water outlet. The house is well organized western house(西四宅) by analysis of Dongseosataek-ron(東西四宅論). Through the analysis, I found that the house has good Pungsu(Fengshui) environment fitted with Pungsu Hyungsei-ron. The house composed of small thatched roof is enclosed several times by low hills of back, left and right side. So it is believed that the site might be carefully evaluated by Yong, Hyoel, Sa, Su of Hyeongsei-ron for knowing whether the site condition could minimize the demage by strong winds and protect from the winter cold wind and secure water for drinking and farming and then selected. The method of Pungsu for evaluating the geographical condition of surrounding of a site is used as a traditional site analysis method for evaluating the suitability of long-term well and safe residence.

• Journal of Yeungnam Medical Science
• /
• v.35 no.2
• /
• pp.199-204
• /
• 2018

Background: The authors have performed ultrasound-guided stellate ganglion block (SGB) in our clinic using a lateral paracarotid approach at the level of the 6th cervical vertebra (C6). Although SGB at C6 is a convenient and safe method, there are ongoing concerns about the weak effect of sympathetic blockade in the ipsilateral upper extremity. Therefore, ultrasound-guided SGB was attempted using a lateral paracarotid approach at the level of the 7th cervical vertebra (C7). This prospective study aimed to compare changes in skin temperature after SGB was performed at C6 and C7, and to introduce a lateral paracarotid approach for SGB. Methods: Thirty patients underwent SGB twice: once at C6 and once at C7. For every SGB, the skin temperature of the patient's hypothenar area was measured for 15 min at 1-min intervals. Skin temperatures before and after SGB and side effects were compared between C6 and C7 groups. Results: The temperature of the upper extremity increased after SGB was performed at C6 and C7. There were significant differences between mean pre-SGB and the largest increases in post-SGB temperatures ($0.50{\pm}0.38^{\circ}C$ and $1.41{\pm}0.68^{\circ}C$ at C6 and C7, respectively; p<0.05). Significantly increased post-SGB temperatures (difference > $1^{\circ}C$) were found in 5/30 (16.7%) and 24/30 (80%) cases for C6 and C7, respectively (p<0.05). There were no significant differences in side effects between SGB performed at C6 or C7 (p>0.05). Conclusion: The lateral paracarotid approach using out-of-plane needle insertion for ultrasound-guided SGB performed at C7 was feasible and more effective at elevating skin temperature in the upper extremity than SGB at C6.

• Korean Journal of Environmental Agriculture
• /
• v.40 no.2
• /
• pp.83-91
• /
• 2021

BACKGROUND: Cultivation area using agricultural plastic film facilities in Korea is rapidly increasing every year; however, it accelerates the salt accumulation in soils due to repeated cultivation and excessive use of chemical fertilizers. Coal ash contains various trace elements and has high potential to be used in agricultural purposes. This research was aimed to improve the quality of salts-accumulated soils and crop growth grown in the plastic film facilities using the soil amendment derived from coal ash and zero-valent iron powder. METHODS AND RESULTS: Soil amendment used in the study was manufactured using coal ash with iron powder and subjected to a typical upland soil for soil quality enhancement and two salts-accumulated soils for crop growth. After one month incubation of the salts-accumulated soils treated with the soil amendment, soil pH increased significantly and soil EC decreased by approximately 50%, compared to the control or the treatment without the soil amendment. Since the soil salts' concentration is proportional to EC, the subjected soil amendment can be proposed as an effective way to overcome soil salts accumulation in agricultural plastic film facilities. For crop growth, the length of roots and stems increased by approximately 10% and the dry weight also increased by a maximum of 75%, compared to the control. CONCLUSION: The soil amendment made from waste resources such as coal ash and zero-valent iron was found to not only be effective in improving salt-accumulated soils and crop yield but also be safe against harmful heavy metals.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2014.10a
• /
• pp.320-323
• /
• 2014

Today is going with the advancement of intelligent transportation systems and traffic environment and helping to provide safe and convenient service through a mobile device work with the popularization of the vehicle black box. The traffic flow by a variety of causes is constantly changing, it is often unable to prepare the driver, depending on external factors can not be controlled by the power of the public, leading to a major accident. The system needs to pass the real-time weather data in the inter-operator to prevent this. The proposed detection algorithm weather information delivered real-time weather information for this paper. The weather condition is detected by using the contrast between the histogram of the motion of the wiper and the clear day algorithm. In general, the wiper is worked in extreme weather conditions that will have a value different contrast due to rain or snow. Situation was considered clear, snowy conditions, such as using it on a rainy situation. First, designated as ROI (Region Of Interest) of the minimum area that can be detected in order to reduce the amount of calculation for the wiper, the wiper, which was detected through the operation of the threshold Thresholding the brightness of the vehicle wiper. In addition, we distinguish the value of each meteorological situation by using contrast. Results was obtained to 80% for the snow conditions, a rainy situation.

• Journal of the Korean Society of Systems Engineering
• /
• v.17 no.1
• /
• pp.65-75
• /
• 2021

When the decommissioning of South Korea nuclear power plants is promoted in earnest with the permanent shutdown of Kori Unit 1 in 2017, a large amount of various types of radioactive waste will be generated. For minimal generation and safe management of decommissioning waste, the waste should be made by appropriate classification of the dismantling waste characteristics in accordance with physical, chemical and radiological characteristics to meet the acceptance criteria of disposal facilities. Replacing the preliminary inspection at the site for the compliance of the waste acceptance criteria (WAC) of medium and low-level radioactive waste with the generator's own radioactive waste certification program (WCP), from the perspective of disposal, the optimization of waste management at the national level contributes to the efficient availability of disposal, such as the processing of non-conforming radioactive wastes at the site. To this end, it is important to evaluate radioactivity in each system and area such as nuclear reactors before decommissioning is carried out in earnest, and the prior removal of harmful wastes is important. From waste collection to waste disposal, decommissioning waste should be managed at each stage in consideration of the acceptance criteria of disposal facilities to minimize the generation of non-conforming waste.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.22 no.1
• /
• pp.43-56
• /
• 2012

Wireless sensor networks consist of numerous small-sized nodes equipped with limited computing power and storage as well as energy-limited disposable batteries. In this networks, nodes are deployed in a large given area and communicate with each other in short distances via wireless links. For energy efficient networks, dynamic clustering protocol is an effective technique to achieve prolonged network lifetime, scalability, and load balancing which are known as important requirements. this technique has a characteristic that sensing data which gathered by many nodes are aggregated by cluster head node. In the case of cluster head node is exposed by attacker, there is no guarantee of safe and stable network. Therefore, for secure communications in such a sensor network, it is important to be able to encrypt the messages transmitted by sensor nodes. Especially, cluster based sensor networks that are designed for energy efficient, strongly recommended suitable key management and authentication methods to guarantee optimal stability. To achieve secured network, we propose a key management scheme which is appropriate for hierarchical sensor networks. Proposed scheme is based on polynomial key pool pre-distribution scheme, and sustain a stable network through key authentication process.