• Strategy21
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• s.38
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• pp.250-286
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• 2015

The main purpose of this article is to provide an understanding on current maritime issues in the Northeast Asia, and thereby help formulating the right strategy for our national security. The article summarizes core arguments in the recently published 『The 21^st Century Maritime Strategies in the Northeast Asia: Dilemma between Competition and Cooperation』. It will help readers to comprehend historical backgrounds as well as recent updates related to maritime issues and strategies in the region. Also, readers may find guidance to conceive their own maritime strategies for the Republic of Korea. Currently, the U.S. is shifting its focus from Atlantic to Pacific, and increasing its naval presence in Asia-Pacific region. Meanwhile, the 21^st century China views the maritime interests as the top priority in its national security and prosperity. PLA Navy's offensive maritime strategies and naval building such as aircraft carriers and nuclear submarines are unprecedented. Japan is another naval power in the region. During the Cold War JMSDF faithfully fulfilled the mission of deterring Soviet navy, and now it is doing its job against China. Lastly, Putin has been emphasizing to build the strong Russia since 2000, and putting further efforts to reinforce current naval capabilities of Pacific Fleet. The keyword in the naval and maritime relations among these powers can be summarized with "competition and cooperation." The recent security developments in the South China Sea(SCS) clearly represent each state's strategic motivations and movements. China shows clear and strong intention to nationalize the islands in SCS by building artificial facilities - possibly military purpose. Obviously, the U.S. strongly opposes China by insisting the freedom of navigation(FON) in international waters as recent USS-Lassen's FON operation indicate. The conflict between China and the U.S. surrounding the SCS seems to be heading towards climax as Russia and Japan are searching for their own national interests within the conflict. Also, the neighboring small and middle powers are calculating their own economic and security interests. This is no exception for us in establishing timely strategies to maximize our own national security. Hopefully, this article leads the readers to the right direction.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.48 no.1
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• pp.17-25
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• 2011

At the computer games, we can experience a variety of environments using a virtual object. It is similar to that be trained in War-game simulator of the defense. Actual soldiers and a computer-generated virtual group(Computer Generated Force: CGF) in 3-D virtual battlefield environment are training. However, path finding algorithm, one of the techniques of simulation models, to the current level only considers the shortest time path. So, this current level at the special situation of the army in the battlefield for selecting the optimal path is limited. The focus of this paper is to select the least-cost path using the deadline with several different mission conditions(METT+TC). For the only shortest time path algorithm and the least-cost path algorithm using dealine,($d_t$, one of METT+TC elements), Its usefulness is verifying the change of the move spent time(t) for all possible paths and the fighting power of the combat troops(Troops ability, a) through a comparison of the total cost of moves(c(t)). According to the results, when considering the deadline, the proposed algorithm saves about 62.5% of the maximum cost.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.4
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• pp.311-316
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• 2020

The main cause of DMSMS is the rapid replacement cycle and short life cycle of parts, according to the development of science, compared to the long life cycle of weapons systems. In particular, the problem of the supply and demand of such parts becomes even more acute during the operation maintenance phase after the mass production and power generation stage. To eliminate DMSMS problems that arise continuously from development to the operation of weapon systems and select the most cost-effective countermeasures to obsolescence, this paper suggests a standard to determine the appropriate time for quantitative performance improvement by conducting total life cycle cost analysis. For such purpose, this study examined the domestic and overseas cost analysis methods and applied it to single domestic weapon system to verify the research. This study responds to the issue of discontinuing components and helps reduce the total life cycle cost of military products.

• Korean Security Journal
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• no.21
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• pp.35-52
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• 2009

The guard system in the last period of the Joseon Dynasty, established at the time of the struggle of invading world powers and the loss of the Dynasty rights, was strengthened to protect the Royal family and the Dynasty from the attacks of foreign powers. While investigating both the military system and the guard system from the beginning of King Gojong's direct royal governing to the time of Japanese annexation of Korea, we realize that the Joseon Dynasty not only lost the support of the public but also had little power to cope with the aggression of foreign countries. The reformation and strengthening by Daewongun, King Gojong's father, was made in preparation for King Gojong's direct royal rule. Nevertheless, the intervention of foreign countries in the domestic affairs of the Joseon Dynasty got worse. As opposed to their intervention, Queen Minbi had engaged in politics, which resulted in murderous attempts on her. The Joseon Dynasty had tried to reform and intensify the guard system. New names such as Muwiso, Chingunyeong, and Siwidai, had been given respectively. Such reformation and intensification had little effect because of two successive victories at the Sino-Japanese War and the Russo-Japanese War of Japan. Japan occupied the Joseon Dynasty by force after all. The guard system of Daehan-jeguk(the Empire of Korea) was eventually incapacitated; an army in the cause of justice was raised instead. However, The state of things and the guard system at that incapacitated period gives a good lesson for the establishment of a modern guard system at the present day.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.3
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• pp.387-395
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• 2013

Recently, several circumferential cracks were found in the control rod drive mechanism (CRDM) nozzles of U.S. nuclear power plants. According to the accident analyses, coolant leaks were caused by primary water stress corrosion cracking (PWSCC). The tensile residual stresses caused by welding, corrosion sensitive materials, and boric acid solution cause PWSCC. Therefore, an exact estimation of the residual stress is important for reliable operation. In this study, finite element simulations were conducted to investigate the effects of the tube geometry (thickness and radius) on the residual stresses in a J-groove weld for different CRDM tube locations. Two different tube locations were considered (center-hole and steepest side hill tube), and the tube radius and thickness variables ($r_o/t$=2, 3, 4) included two different reference values ($r_o$=51.6, t=16.9mm).

• Journal of Fashion Business
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• v.15 no.5
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• pp.69-86
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• 2011

The objective of this research is to unveil the dynamic changes of the trends in wedding dresses during the 20th Century. The studies were carried out in two forms; firstly by observing the actual wedding dresses worn by people at that time, and secondly by conducting formative comparisons between those dresses with the ones appeared in movies corresponding to that period. Movies provide an invaluable insight into the era's wedding dresses fashion trends since they function as intimate bridges in connection with the time's audience, and the visible imageries accurately reflect the characteristics embedded within that time frame. As there are no precedent studies regarding this topic, this thesis can serve as vital research data for the wedding dress industry. Research data regarding the actual wedding dresses were collected from books and museum web sites. The object of movies were films produced before World War II that contained both the background settings of the 20th Century and wedding dresses, of which photographic imageries were captured. Research analysis was then conducted by merging these data with findings from relevant books and internet materials. The results of the thesis are as the following: The 1900s was an extension of the 19th Century's popular fashion trend which can be characterized as the S curve silhouettes of the Edwardian period when long trains and long veils symbolized wealth and social power. In the 1910s, high waist silhouettes with soft wrinkles were prevalent as attire suitable for active mobility with practical functionality were highly regarded. During the 1920s, the flapper style became the dominant trend. Hem lines of the skirts were curled in the form of the scallop and laces were the most widely used raw materials. By the 1930s, wedding dresses that reinterpreted the glamorous sheath lines, practical two piece styles, and retro-styles became predominant. The 1940s saw the advent of ready-made wedding dresses made of synthesized materials; practical military style suits and casuals sometimes substituted the wedding dresses. And although the wedding dresses in the movies were primarily costumes to express the personalities of the characters, they were also reinterpreted as manifestations of the formative characteristics of each relative period that pursued very distinct and diverse features.

• Journal of the Korea Concrete Institute
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• v.28 no.6
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• pp.673-683
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• 2016

In recent years, frequent terror or military attack by explosion, impact, fire accidents have occurred. Particularly, World Trade Center collapse and US Department of Defense Pentagon attack on Sept. 11 of 2001. Also, nuclear power plant incident on Mar. 11 of 2011. These attacks and incidents were raised public concerns and anxiety of potential terrorist attacks on major infrastructures and structures. Therefore, the extreme loading researches were performed of prestressed concrete (PSC) member, which widely used for nuclear containment vessel and gas tank. In this paper, to evaluate the blast resistance capacity and its protective performance of bi-directional unbonded prestressed concrete member, blast tests were carried out on $1,400{\times}1,000{\times}300mm$ for reinforced concrete (RC), prestressed concrete without rebar (PSC), prestressed concrete with rebar (PSRC) specimens. The applied blast load was generated by the detonation of 55 lbs ANFO explosive charge at 1.0 m standoff distance. The data acquisitions not only included blast waves of incident pressure, reflected pressure, and impulse, but also included displacement, acceleration, and strains at steel, concrete, PS tendon. The results can be used as basic research references for related research areas, which include protective design and blast simulation under blast loading.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.9
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• pp.812-817
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• 2016

This paper dealt with electrical and optical requirements of naval vessel's LED luminaires. And the products have been tested to determine whether the products meet these requirements or not. This study analyzes the cost-effectiveness of the LED luminaires which have been implemented for the application to naval vessel since 2012. The LED requirements were proposed based on comparison among other standards/specifications such as Korean Industrial Standard(KS), Korean Defense Specification(KDS) and US Navy Military Specification(MIL). Application of the proposed requirements were then be verified by analyzing and testing the electrical and optical characteristics of both fluorescent Luminaires and LED luminaires, and the LED luminaires were installed to A1 naval vessels according to the proposed requirements. As results, approximately 40% of power consumption was saved by using LED luminaires compared to using fluorescent luminaires while luminous flux was increased by 10~15%. Moreover, using LED luminaires of the proposed requirements exhibited the effect of reducing approximately 4,900 fluorescent luminaires in 10 naval vessels in the time period between 2012 to 2015, which is equivalent to cost reduction of \0.56M approximately. Such cost reduction is further expected considering the LED luminaires will continue to be applied to naval vessels in the future.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.3
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• pp.623-628
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• 2009

The emergence of compact and low-power wireless communication sensors and actuators in the technology supporting the ongoing miniaturization of processing and storage allows for entirely the new kinds of embedded systems. These systems are distributed and deployed in environments where they may have been designed into a particular control method, and are often very dynamic. Collection of devices can communicate to achieve a higher level of coordinated behavior. Wireless sensor nodes deposited in various places provide light, temperature, and activity measurements. Wireless sensor nodes attached to circuits or appliances sense the current or control the usage. Together they form a dynamic and multi-hop routing network connecting each node to more powerful networks and processing resources. Wireless sensor networks are a specific-application and therefore they have to involve both software and hardware. They also use protocols that relate to both applications and the wireless network. Wireless sensor networks are consumer devices supporting multimedia applications such as personal digital assistants, network computers, and mobile communication devices. Wireless sensor networks are becoming an important part of industrial and military applications. The characteristics of modem embedded systems are the capable of communicating adapting the different operating environments. In this paper, We designed and implemented sensor network system which shows through host PC sensing temperature and humidity data transmitted for wireless sensor nodes composed wireless temperature and humidity sensor and designs sensor nodes using embedded system with the intention of studying USN.

• Journal of KIISE:Computing Practices and Letters
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• v.11 no.2
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• pp.149-156
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• 2005

The HLA is the simulation architecture standard that the civilian and military simulation communities are deeply interested in. We can find various successful practices applying HLA to constructive simulations such as war games in domestics and overseas. However, any case of real-time distributed simulations has not been reported. The reason is that a message transmission period via RTI in a network layer varies according to computing power, simulation nodes, transmission types, and packet size; further a message processing time in an application layer depends on its processing methods, thus too difficult to set up real-time constraints for the enhancement of a real-time resolution. Hence, in this paper we have studied the real-time constraints of RTI for the development of the M-SAM simulator. Thus we have developed a HLA based pilot simulator using 6 PC's in LAN and then measured and analysed the performance of the RTI. As the results of our work, we could obtain the quantitative values for message delay, RTI overhead and RTI packet transmission ratio by a real operation scenario and loads, which are not shown in the previous works. We also expect that the results can be used as a guideline to set up the number of targets, transmission frequency and message processing method in the development of the M-SAM simulator and similar applications.