• Structural Monitoring and Maintenance
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• v.8 no.4
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• pp.345-360
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• 2021

This paper presents an analytical approach to calculate the buckling load of the cylindrical ring structures subjected to both hydrostatic and hydrodynamic pressures. Based on the conservative law of energy and Timoshenko beam theory, a theoretical formula, which can be used to evaluate the critical pressure of buckling, is first derived for the simplified cylindrical ring structures. It is assumed that the hydrodynamic pressure can be treated as an equivalent hydrostatic pressure as a cosine function along the perimeter while the thickness ratio is limited to 0.2. Note that this paper limits the deformed shape of the cylindrical ring structures to an elliptical shape. The proposed analytical solutions are then compared with the numerical simulations. The critical pressure is evaluated in this study considering two possible failure modes: ultimate failure and buckling failure. The results show that the proposed analytical solutions can correctly predict the critical pressure for both failure modes. However, it is not recommended to be used when the hydrostatic pressure is low or medium (less than 80% of the critical pressure) as the analytical solutions underestimate the critical pressure especially when the ultimate failure mode occurs. This implies that the proposed solutions can still be used properly when the subsea vehicles are located in the deep parts of the ocean where the hydrostatic pressure is high. The finding will further help improve the geometric design of subsea vehicles against both hydrostatic and hydrodynamic pressures to enhance its strength and stability when it moves underwater. It will also help to control the speed of the subsea vehicles especially they move close to the sea bottom to prevent a catastrophic failure.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2023.05a
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• pp.208-209
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• 2023

Intelligent maritime traffic information service for maritime traffic safety operates a service that provides safe and efficient optimal safety routes considering information such as water depth, maritime safety law, weather information, and fuel consumption. However, from a service user's point of view, they prefer a route that suits their personal navigation experience and style, such as unnecessary detours and conservative safety distances for maritime objects. In this study, the optimal safety route can be extracted based on the experience of service users without reflecting the separate maritime environment by adjusting the weight of the trunk line for the area where the ship frequently navigates with the ship's track data collected through LTE-M model was studied.

• Korean journal of communication and information
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• v.40
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• pp.150-191
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• 2007

Defamation lawsuits of public figures against media have been an issue since Roh government set in. Dissension between the government and media has probably acted as the key factor on this problem. Accordingly, arguments on the defamation lawsuits of public figures occurred the political issues such as opposition between the Progressive and the Conservative Parties or between the ins and the outs and showed the limits to suggest an appropriate judgment or solution. This study will analyze how the court makes its judgement on their rights and the limits by understanding the characteristic and the problem of defamation lawsuits made by senior government officials including a politician, the government, the president, and etc. As results, the defamation lawsuits of politicians and senior government officials showed specially noteworthy matters in salvation (damage suits), the amount claimed, court costs, ratio of winning lawsuits, and etc. The result on the tendency of the court decision showed the following matters in confusion: it holds the media responsible for the burden of proof by applying the inappropriate criterion; The applied laws, especially in the inferior court decision, do not show the consistency of the burden of proof between the misconception/ intention (malice)/ accident/ purpose of slander on the legal principles of public figures. Therefore, this study suggests the court to apply an appropriate law, let alone regulating the Anti-SLAPP law, so that it curtails the rights of public figures; limits the salvation of damage suit; and protects the right only in the case of false accusation by applying the existing law of "the Protection of the Deceased's Defamation Law." In order to dissolve the confusion when applying the laws on the public figures, the study insists the court to positively apply the Constitutional Court made criterion on "people" and "content." The study also insists to distinguish "intention(malice)," "accident," and "purpose of slander" and variant sorts of the burden of proof should be applied to each.

• Journal of the Korea Concrete Institute
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• v.19 no.5
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• pp.585-593
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• 2007

This paper presents a model for durability evaluation of concrete structures exposed to marine environment, considering mainly a build-up of surface chloride $(C_s)$ as well as diffusion coefficient (D) and chloride threshold level $(C_{lim})$. In this study, time dependency of $C_s$ and D were extensively studied for more accurate evaluation of service life of concrete structures. An analytical solution to the Fick's second law was presented for prediction of chloride ingress for time varying $C_s$. For the time varying $C_s$, a refined model using a logarithm function for time dependent $C_s$ was proposed by the regression analysis, and averaging integrated values of the D with time over exposed duration were calculated and then used for prediction of the chloride ingress to consider time dependency of D. Durability design was also carried out for railway concrete structures exposed to marine environment to ensure 100 years of service life by using the proposed models along with the standard specification on durability in Korea. The proposed model was verified by the so-called performance-based durability design, which is widely used in Europe. Results show that the standard specification underestimates durability performances of concrete structures exposed to marine environment, so the cover depth design using current durability evaluation in the standard specifications is very much conservative. Therefore, it is found that utilizing proposed models considering time dependent characteristics of $C_s$ and D can evaluate service lift of concrete structures in marine environment more accurately.

• Journal of Environmental Policy
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• v.13 no.4
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• pp.135-159
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• 2014

Industrial insect is defined as the insect utilized in industries that creates added value. Most of the industrial insects used in Korea are exotic species that are introduced through artificial means. Despite the rapid expansion of market for industrial insects, the system for risk assessment of industrial insects is not being adequately conducted. Although Korea carries out a risk assessment for the species designated as disease and insect pest by Animal and Plant Quarantine Agency, far too little consideration is being given to overall ecosystem, as the control system is covered in the Plant Quarantine Law. To solve this problem, we analyzed the Korean risk assessment system and looked at systems in other countries. The results show that it is essential for stakeholders to reach an agreement to set up fundamental directions for the system. Unless the integration system of taxonomical and ecological information is prepared, the ecological risk assessment should be conservative to protect ecosystems and should also follow the precautionary principle. It also requires cooperation among the ministries. In addition, the results indicated that a differentiation between risk assessment and screening is urgent. Several solutions such as setting up clear objectives in both assessment and screening stages, target species, steering organization and assessment criteria assessment systems from were proposed as practical institutional strategies. Among many foreign countries the assessment system from Ireland equally considers various factors such as economical, ecological safety and management aspects, It is also based on precautionary principle to fulfil its original purpose. It was suggested that the Ireland system would be the best reference that can be modified and applied into the Korean system by considering distinct characteristics of the industrial insects.

• Korean Security Journal
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• no.39
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• pp.185-215
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• 2014

Since North Korea has used terror crime as a means of unification under communism against South Korea, South Korea has been much damaged until now. And the occurrence possibility of terror crime by North Korean authority is now higher than any other time. The North Korean terror crimes of Kim Il Sung era had been committed by the dictator's instruction with the object of securing governing fund. However, looking at the terror crimes committed for decades during Kim Jung Il authority, it is revealed that these terror crimes are expressed as a criminal behavior because of the conflict to accomplish the power and economic advantage non powerful groups target. This study focused on the power conflict in various causes of terror crimes by applying George B. Vold(1958)'s theory which explained power conflict between groups became a factor of crime, and found the aspect by ages of terror crime behavior by North Korean authority and responding plan to future North Korean terror crime. North Korean authority high-ranking officials were the Labor Party focusing on Juche Idea for decades in Kim Il Sung time. Afterwards, high-ranking officials were formed focusing on military authorities following Military First Policy at the beginning of Kim Jung Il authority, rapid power change has been done for recent 10 years. To arrange the aspect by times of terror crime following this power change, alienated party executives following the support of positive military first authority by Kim Jung Il after 1995 could not object to forcible terror crime behavior of military authority, and 1st, 2nd Yeongpyeong maritime war which happened this time was propelled by military first authority to show the power of military authority. After 2006, conservative party union enforced censorship and inspection on the trade business and foreign currency-earning of military authority while executing drastic purge. The shooting on Keumkangsan tourists that happened this time was a forcible terror crime by military authority following the pressure of conservative party. After October, 2008, first military reign union executed the launch of Gwanmyungsung No.2 long-range missile, second nuclear test, Daechung marine war, and Cheonanham attacking terror in order to highlight the importance and role of military authority. After September 2010, new reign union went through severe competition between new military authority and new mainstream and new military authority at this time executed highly professionalized terror crime such as cyber/electronic terror unlike past military authority. After July 2012, ICBM test launch, third nuclear test, cyber terror on Cheongwadae homepage of new mainstream association was the intention of Km Jung Eun to display his ability and check and adjust the power of party/military/cabinet/ public security organ, and he can attempt the unexpected terror crime in the future. North Korean terror crime has continued since 1980s when Kim Jung Il's power succession was carried out, and the power aspect by times has rapidly changed since 1994 when Kim Il Sung died and the terror crime became intense following the power combat between high-ranking officials and power conflict for right robbery. Now South Korea should install the specialized department which synthesizes and analyzes the information on North Korean high-ranking officials and reinforce the comprehensive information-collecting system through the protection and management of North Korean defectors and secret agents in order to determine the cause of North Korean terror crime and respond to it. And South Korea should participate positively in the international collaboration related to North Korean terror and make direct efforts to attract the international agreement to build the international cooperation for the response to North Korean terror crime. Also, we should try more to arrange the realistic countermeasure against North Korean cyber/electronic terror which was more diversified with the expertise terror escaping from existing forcible terror through enactment/revision of law related to cyber terror crime, organizing relevant institute and budget, training professional manpower, and technical development.

• The Journal of Korean Society for School & Community Health Education
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• v.5
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• pp.107-122
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• 2004

To correctly plant the value of sex to the juvenile, we cannot overemphasize the importance of the sexual education in schools. Therefore, the study for teachers' consciousness and view of sex is also necessary, because they are subjects of education and role-models of sex of their students. Especially, if teachers are over fifty in age, it is more important, because it is obvious, as they are in positions of managers and directors of education, that their view of sexual value and consciousness are influencing the aim of education and the course of education. Hereby this study was conducted to check their sexual consciousness, attitude, and condition and to prepare for the basic data needed for the development of a sexual education program suitable to them. The methods of the survey of this study are applied by modifying or supplementing those of precedented studies. They are used after analyzing reliance of items according to Cronbach's $\alpha$ figure calculating law, and modifying or supplementing items lower in reliance. The questionnaire survey was conducted among 1,000 randomly selected from teachers working in middle and high schools in Korea from June 14th in 2004 to June 30th. The survey analyzed 632 questionnaires suitable to it. The outcomes of the survey of this study are like the following: First, the objects of the survey consist of 64.6% men and 35.4% women. Among them, 41.1% are under fifty and the rest are over fifty. As for the periods of marriage, 15.5% are unmarried, 16.3% are under ten years, 18.0% are between ten and twenty, and 50.2% are over twenty. Second, with reagard to sex, 25.6% admit the necessity of a heterosexual friend. 32.0% say that they are conservative to sex. 54.1% are taught sexual education. 67.1% attribute sexual education to nursing teachers. Third, among those who answer that they enoughly know the concept of sex, seenig by age, 25.0% are under fifty and 58.1% are over fifty. Seening by the periods of marriage, 9.2% are unmarried, 28.2% are under ten, 49.1% are between ten and twenty, and 59.0% are over twenty. Among those who answer that they enoughly know the concepts of sexual harassment and sexual violence, seenig by age, in the turns by above-mentioned order, each 47.7% and 76.3%. Seening by the periods of marriage, each 9.2%, 28.2%, 49.1%, and 59.0%. Fourth, among those who answer that "teachers also need sexual education and sexual counsel," by age, each92.7% and 91.4%. By the periods of marriage, each 89.8%, 95.2%, 89.4%, and 92.4%. As a matter of course, we can infer the necessity of the sexual education and sexual counsel for teachers. Fifth, among those who answer that they are satisfied with their sexuality, by age, each 41.1% and 61.3%. By the period of marriage, each 4.1%, 63.1%, 64.1%, and 61.5%. As for the sexual desire like spiritual intercourse, physical intercourse containing sexuality, by age, each 71.9% and 93.5%. By the periods of marriage, each 54.0%, 81.5%, 90.3%, and 93.0%. The survey shows that those over fifty and having long marriage are feeling the stronger desire towards sexuality. Through the outcomes of this survey, a few suggestions are possible: First, it is necessary to check of the teachers' view of sexual value and to study deep about the sexual tendency of them in twenties, thirties, and forties. It is to make them teach their students on the firm basis, and also to develop suitable sexual education and counsel program.

• Journal of radiological science and technology
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• v.39 no.4
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• pp.509-516
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• 2016

A dental panoramic radiography which usually uses low level X-rays is subject to the Nuclear Safety Act when it is installed for the purpose of education. This paper measures radiation dose and spatial dose rate by usage and thereby aims to verify the effectiveness of radiation safety equipment and provide basic information for radiation safety of radiation workers and students. After glass dosimeter (GD-352M) is attached to direct exposure area, the teeth, and indirect exposure area, the eye lens and the thyroid, on the dental radiography head phantom, these exposure areas are measured. Then, after dividing the horizontal into a $45^{\circ}$, it is separated into seven directions which all includes 30, 60, 90, 120 cm distance. The paper shows that the spatial dose rate is the highest at 30 cm and declines as the distance increases. At 30 cm, the spatial dose rate around the starting area of rotation is $3,840{\mu}Sv/h$, which is four times higher than the lowest level $778{\mu}Sv/h$. Furthermore, the spatial dose rate was $408{\mu}Sv/h$ on average at the distance of 60 cm where radiation workers can be located. From a conservative point of view, It is possible to avoid needless exposure to radiation for the purpose of education. However, in case that an unintended exposure to radiation happens within a radiation controlled area, it is still necessary to educate radiation safety. But according to the current Medical Service Act, in medical institutions, even if they are not installed, the equipment such as interlock are obliged by the Nuclear Safety Law, considering that the spatial dose rate of the educational dental panoramic radiography room is low. It seems to be excessive regulation.