• Proceedings of the KACD Conference
• /
• 2003.11a
• /
• pp.606-606
• /
• 2003

There have been many studies that have evaluated success and failure of endodontic treatment (Nair, Sjogren), but there is remarkably limited information concerning the specific microorganisms that are involved in the teeth with treatment failure. Microorganisms that survive root canal treatment to cause a persistent infection must possess specific characteristics to avoid the host defense. These can be broadly classified as; 1. Sequestration：A physical barrier between the microbe and the host. 2. Cellular evasion：Microorganisms avoid leukocyte dependent antibacterial mechanisms. 3. Humoral evasion：Extracellular bacteria avoid the hosts antibodies and complement.(omitted)

• Journal of the Korean Institute of Navigation
• /
• v.6 no.1
• /
• pp.41-59
• /
• 1982

In the Sailing Rules of International Regulation for Preventing Collisions at Sea, 1972, any definite distance between two vessels approaching each other is not referred for adequate maneuvering to avoid collision. At sea the officer in charge of bridge duty is required to guess safe distance before he takes maneuvering actions needed to avoid collision. Papers on safe distances calculated on the base of the motiional characteristics of ships for collision avoiding actions are very few. In this paper, the minimum safe approaching distances necessary for actions to be taken to avoid collision are calculated in numerical numbers definitely by mathematic formula based on the maneuvering indices got from experiments of actual ships. On the assumption that two vessels same in size and conditions are approaching each other, the author calculated the minimum safe approaching distance as 4.5 times, sufficient safe approaching one as 9.0 times the length of the ship involved in head-on situation and 5.0 times, 10 times respectively the length of the ship in each case mentioned above in crossing situation.

• Structural Engineering and Mechanics
• /
• v.37 no.6
• /
• pp.633-648
• /
• 2011

This paper investigates the aspect-ratio locking of the isoparametric 8-node quadrilateral (QUAD8) element. An important finding is that, if finite element solution is carried out with in exact arithmetic (i.e., with no truncation and round off errors), the locking tendency of the element is completely avoided even for aspect-ratios as high as 100000. The current finite element codes mostly use floating point arithmetic. Thus, they can only avoid this locking for aspect-ratios up to 100 or 1000. A novel method is proposed in the paper to avoid aspect-ratio locking in floating point computations. In this method, the offending terms of the strain-displacement matrix (i.e., $\mathbf{B}$-matrix) are multiplied by suitable scaling factors to avoid ill-conditioning of stiffness matrix. Numerical examples are presented to demonstrate the efficacy of the method. The examples reveal that aspect-ratio locking is avoided even for aspect-ratios as high as 100000.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• v.1
• /
• pp.145-150
• /
• 2006

The paper deals with integrated navigation and sense & avoid systems for small unmanned aerial vehicles (UAV). First an introduction to the current UAV activities of the institute is given. It is followed by an overview about the integrated navigation system developed for small UAVs. The system is based on a tightly-coupled GPS/INS architecture. But instead of using delta-ranges, time-differenced carrier phases are used to aid the INS. Finally, results from navigation filter validation in flight tests are presented. After that an overview about sense and avoid strategies for application in small unmanned aircraft is given. From this a guideline for developing such a system for the institute's UAVs is presented.

• Journal of the Korean Institute of Navigation
• /
• v.12 no.1
• /
• pp.71-84
• /
• 1988

For traffic proceeding in random directions on a plane surface the frequency of collision, if no avoiding action in taken ,is approximately proportional to the square of the traffic density and directly proportional to the size and speed of the ship, Avoiding is normally taken and the rte of collisions is therefore also governed by additional factors such as the visibility, the effectiveness of the collisionavoidance rules, the competence of personnel or watchkeeping attitude, the maneuverability of the ship and the efficiency of radar and other equipments. From the viewpoint of watchkeeper who is responsible for maneuvering, watchkeeping attitude such as lookout and action to avoid collision is the most controllable factor among those mentioned above. In practice, according to the investigation of the institution of marine courts, about 50% co collisions occurred is caused by disorbedience to steering and sailing rules of international regulations for preventing collision at sea including lookout. So we classify the process of collisions with first sight of another ship , assessment of risk of collisions and action to avoid collisions and make a factural survey about lookout and action to avoid collisions from the point on "time" and " distance", namely relationship among ship's size, speed, first sight time of another ship, action to avoid collisions ,and distance from sight of another ship to collision occurred. According to the results of the actual survey , we come to conclude that most of collisions occurred are due to improper lookout and ineffective action to avoid collision which means time lag from first sight of another ship to time of action taken to avoid collision is relatively long. is relatively long.

• Journal of Digital Convergence
• /
• v.18 no.12
• /
• pp.217-229
• /
• 2020

Globally, information protection of organization has become an essential management factor, and organizations continue to invest high-level resources for information security. Security threats from insiders are not decreasing. The purpose of this study is to present the antecedence factors to mitigate the role conflict that is the cause of the security avoid behavior. For the study, a survey was conducted for employees of organizations with information security policies, and structural equation modeling was conducted using a total of 383 samples for hypothesis verification. As a result of the analysis, role conflict increased avoid behavior, and goal difficulty, goal specificity, justice, and trust mitigated role conflict. In particular, justice influenced the reduction of role conflict and avoid behavior through trust. The implications were to present the causes and mitigation factors for avoid behavior of employee, and it is judged that it will help the organization to establish a security strategy.

• Journal of the Society of Naval Architects of Korea
• /
• v.55 no.4
• /
• pp.321-329
• /
• 2018

Resonance phenomena occurs at large vertical pump which is operating to cool down the hot steam using sea water in the power plant. To avoid the resonance, the natural frequency needs to be isolated about 20% from motor operating speed. Yet, excessive vibration occurs especially at low tide. At first, natural frequency of the whole pump system and each part is calculated using ANSYS. As it is revealed in the previous journal papers that only circular pipe part is related to resonance, the FSI technique is applied for free vibration analysis. The natural frequency is reduced to 60% (compared to that) of the frequency measured in air as it is similar to other published results. And the frequency obtained by finite element analysis is almost same to that obtained from modal test. Based on the accurate finite element model and analysis, design change is tried to avoid the resonance by changing the thickness of pipe and base supporting plate. In stead of doing optimization process, design sensitivity is computed and used to find such designs to avoid resonance.

• Korean Journal of Logic
• /
• v.16 no.3
• /
• pp.381-406
• /
• 2013

This paper deals with the question whether the para-completeness theory of Kripkian style can avoid the revenge problem. According to the para-completeness theory, there are some sentences that are neither true nor false. And the liar sentence is the exemplar of such sentences. But the para-completeness theory has been criticised to give rise to the revenge problem, since Kripke suggested his theory. Maudlin argues that he can construct the para-completeness theory which avoids the problem by appealing to his foundationalist semantics. The aim of this paper shows that the para-completeness theory, including Maudlin's, cannot avoid the problem. Furthermore, it is argued that Maudlin's view is ad hoc suggestion just to avoid the problem.

• The Journal of Korean Obstetrics and Gynecology
• /
• v.21 no.3
• /
• pp.143-166
• /
• 2008

Purpose: The purpose of this study is to ascertain the awareness or incidence of SHP and postnatal care. Methods: We analyzed the results of Questionnaires for 104 women who have experienced childbirth within the last 10 years and examined June 2007 to December 2007. We divided to three groups according to age and investigated. Results: 1. Awareness of SHP and postnatal care. Responses about "How informed are you about the syndrome known in Korea as SHP?", Person's ration who know is 72.11%. Responses about "Are you aware of current traditional postnatal practices in Korea?", Person's ration who know is 80.77%. "Do you think that postnatal care as practised is Korea is necessary?", Person's ration who know is 84.62%. "Do you think that in general postnatal care is necessary?", Person's ration who know is 93.27%. "Do you believe, if you are unable to practice postnatal care, you will subsequently develop health problems?", Person's ration who know is 91.35%. 2. Relevant comments of postnatal care. Responses about lifestyle after childbirth are Prevent bodily hard work 35.37%, Prevent cold stimulus 27.21 %, Hold body warmly 17.69%, Psychologically comfortably 7.48%, Eat good food 7.48% Etc 10.88%. Foods after childbirth are Avoid cold foods 22.38%, Avoid hard foods 17.48%, avoid hot foods 16.78%, avoid salty foods 10.49%, avoid excitative foods 8.39%. Medication after childbirth are Oriental medicine and restorative medicine 21.24%, iron was 15.04%, pumpkin 15.04%, vitamin 9.73%, calcium and snakehead each 7.96%. 3. Postnatal care practices Correlation postnatal care practices with present health condition are 19 items of 31 items. Conculsion: We hope these results could be helpful to diagnosis and treatment of SHP.

• Journal of the Korean Society for Aviation and Aeronautics
• /
• v.25 no.4
• /
• pp.83-90
• /
• 2017

Unmanned Aerial Vehicles(UAVs) require collision avoidance capabilities equivalent to the capabilities of manned aircraft to enter the airspace of manned aircraft. In the case of Visual Flight Rules of manned aircraft, collision avoidance is performed by 'See-and-Avoid' of pilots. To obtain those capabilities of UAVs named as 'Sense-and-Avoid', sensor-system-based intruder tracking and collision avoidance methods are required. In this study, a multi-sensor-based tracking, data fusion, and collision avoidance algorithm is designed by using a model-based design tool MATLAB/SIMULINK, and validations of the designed model and code using numerical simulations and processor-in-the-loop simulations are performed.