• Journal of Institute of Control, Robotics and Systems
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• v.7 no.1
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• pp.1155-1161
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• 2001

We propose an adaptive nonlinear control algorithm for high precision tracking and stabilization of LOS(Line-of-Sight). The friction parameters of the LOS gimbal are estimated by off-line evolutionary strategy and the friction is compensated by estimated friction compensator. Especially, as the nonlinear control input in a small tracking error zone is enlarged by the nonlinear function, the steady state error is significantly reduced. The proposed algorithm is a direct adaptive control method based on the Lyapunov stability theory, and its convergence is guaranteed under the limited modeling error or torque disturbance. The performance of the pro-posed algorithm is verified by computer simulation on the LOS gimbal model of a moving vehicle.

• IE interfaces
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• v.20 no.3
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• pp.395-406
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• 2007

In the telecommunication industry, estimation of the cost of network facilities is very important since depreciation cost of the facilities accounts for a large portion of the product cost. Moreover, cost estimation in the industry becomes more difficult because of increasing indirect cost upon digital convergence, expanding multi-purpose facilities, complexity of service product, etc. Nevertheless, not much seem to have been done in improving estimation methodology of the cost of network facilities. As a result, the quality of cost information on network facilities has deteriorated, and now even decision-makers in the industry dismiss the information. Recently, two major telecommunication companies adopted a new network cost estimation method to deal with the issue. In this paper, we study the concept of new cost estimation method and the procedure to develop and apply it. We also suggest the method to carry out the cost allocation using Matlab which is more efficient and time-saving than other commercial cost calculation packages.

• Journal of Microbiology and Biotechnology
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• v.29 no.12
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• pp.1873-1881
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• 2019

The innate immune response serves as a first-line-of-defense mechanism for a host against viral infection. Viruses must therefore subvert this anti-viral response in order to establish an efficient life cycle. In line with this fact, Kaposi's sarcoma-associated herpesvirus (KSHV) encodes numerous genes that function as immunomodulatory proteins to antagonize the host immune system. One such mechanism through which KSHV evades the host immunity is by encoding a viral homolog of cellular interferon (IFN) regulatory factors (IRFs), known as vIRFs. Herein, we summarize recent advances in the study of the immunomodulatory strategies of KSHV vIRFs and their effects on KSHV-associated pathogenesis.

• IE interfaces
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• v.25 no.4
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• pp.431-440
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• 2012

Since pooling is a popular scheme in many areas to attain operational excellence, many researchers investigated the performance of pooling systems. However, rare research could be found on pooling with game situation which has much applicability to real world phenomenon. We analyze the performance of noncooperative pooling system with two servers having different sharing capacity. We investigate the sensitivity of the advantage of capacity pooling on the variation of system parameters, including sharing capacity numbers, pooling probability, pooling strategy and traffic intensity. As a result, we suggest an efficient control policy which facilitate the performance of pooling in a game situation.

• International Journal of Reliability and Applications
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• v.7 no.1
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• pp.71-77
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• 2006

The market for second hand products has been growing for a variety of reasons (e.g., new products appearing at a faster rate and the expected life of products increasing due to rapid advances in technology). The demand for warranties for second-hand products has been growing along with the growth of the market for second-hand products. Warranty for new products (consumer durables, industrial and commercial, and specialized defense products) has received a lot of attention. In contrast, warranties for second-hand product have received very little attention. Often, dealers of second-hand product such as cars offer 2D-warranties (Year and Kilometers). The expected warranty cost associated with a second-hand product for 2D-Policies is a function of the age of the item and its usage (as it affects failures over the warranty period), the warranty terms and the servicing strategy used by the dealer. This paper deals with development of models for warranty cost analysis along with the decision on sale price and warranty cover for 2D-Warranty policies associated with sale of second-hand products.

• Maritime Security
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• v.3 no.1
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• pp.115-140
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• 2021

The South China Sea is a significant maritime shipping route with abundant submarine and fishing resources. Over 40,000 ships pass through the South China Sea every year, constituting around 50% of global shipping and 66% of crude oil. In particular, 30% of Korea's import cargo and 90% of energy imports pass through this body of water. The US and China realized the significance of this sea area from early on and are embodying national interest through maritime security at the national strategic level by implementing the 'Indo-Pacific' and 'One Belt One Road' strategies, respectively. Such geopolitical conflicts are manifested in the 'freedom of navigation operations' by the US in the South China Sea. Despite its significance, there is a lack of studies in Korea on the freedom of navigation operations, and most previous studies only focus on analyzing international law and agreements. This article examines the origin and background of the strategic perception of the freedom of navigation operations and derives implications for the peace and security of the Korean Peninsula as the strategic competition between the US and China continues.

• Maritime Security
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• v.1 no.1
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• pp.93-117
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• 2020

Four cargo ships were ambushed by bombs in 2019 while navigating in the Strait of Hormuz. It was not clear who attacked those ships, however, many nations including the United States argued that it was Iran due to several reasons. The United States established the maritime collective defense system named International Maritime Security Construct (IMSC) in order to protect the maritime security in the Strait of Hormuz, without disclosure against whom it is aimed. Persian, who uses the Persian language unlike other countries in the Middle East, is the major ethnic group in Iran, and most of them believe Shi'ah Islam while most of the Arabs in the Gulf countries adhere to Sunni Islam. It seems that historic and religious motives caused the bipolar system in the Middle East, however, it is plausible to analyze the system of international affairs in the Middle East via defensive or structural realism. Iran has attempted to maintain its hegemony in the region by supporting Shi'ah muslims in the neighboring countries as well as in the world by using military and economic means. In this context, Iran's maritime strategy is to maintain its maritime hegemony on the Persian Gulf via countering threats and cooperating with friendly navies by using the Islamic Republic of Iran Navy(IRIN) and the Islamic Revolutionary Guard Corps Navy(IRGCN). IRIN acts like other navies in the world: protecting national interest at sea, expending its operational areas to the outer seas, and enhancing cooperation with other navies. Meanwhile, IRGCN plays a role as an asymmetric force at sea. It is composed of small and fast asymmetric assets, which can ambush ships fast and furious. Considering the poor study for Iran's maritime strategy in Korea, analyzing the strategy is meaningful for the Republic of Korea Navy, which has operated the Cheonghae Unit for more than ten years since it has extended its operational area over the Strait of Hormuz. In order not to be drawn into the conflict in the Strait, research on the maritime strategy of Iran and other countries in the Middle East should be started.

• Wind and Structures
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• v.18 no.6
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• pp.693-715
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• 2014

Stochastic processes are used to represent phenomena in many diverse fields. Numerical simulation method is widely applied for the solution to stochastic problems of complex structures when alternative analytical methods are not applicable. In some practical applications the stochastic processes show non-Gaussian properties. When the stochastic processes deviate significantly from Gaussian, techniques for their accurate simulation must be available. The various existing simulation methods of non-Gaussian stochastic processes generally can only simulate super-Gaussian stochastic processes with the high-peak characteristics. And these methodologies are usually complicated and time consuming, not sufficiently intuitive. By revealing the inherent coupling effect of the phase and amplitude part of discrete Fourier representation of random time series on the non-Gaussian features (such as skewness and kurtosis) through theoretical analysis and simulation experiments, this paper presents a novel approach for the simulation of non-Gaussian stochastic processes with the prescribed amplitude probability density function (PDF) and power spectral density (PSD) by amplitude modulation and phase reconstruction. As compared to previous spectral representation method using phase modulation to obtain a non-Gaussian amplitude distribution, this non-Gaussian phase reconstruction strategy is more straightforward and efficient, capable of simulating both super-Gaussian and sub-Gaussian stochastic processes. Another attractive feature of the method is that the whole process can be implemented efficiently using the Fast Fourier Transform. Cases studies demonstrate the efficiency and accuracy of the proposed algorithm.

• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.6
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• pp.679-688
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• 2015

Stability and security of energy resources are one of the most important factors for a national-development. In this research, we analyzed the Republic of Korea's policy making system on energy security and identified the problems from an innovation system perspective. In terms of the actors, they had limitations that ROK's navy do not have enough strategic plan for energy transportation. The links between innovation actors except defense area were relatively good, but links between the military area(navy) and other innovation actors had weak linkage. The infrastructure did't have enough consideration for military force development. For the institution; the role of the military area on energy security was not completely established. Therefore, participation of the defense area(navy) is required to be stated institutionally.

• Journal of Information Management
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• v.37 no.3
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• pp.99-115
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• 2006

The purpose of this study is to build new management strategy of special libraries in the field of science and technologies. Though information service of digital libraries were developed very much due to IT technologies, management condition of special libraries is getting more worse. Immediate cause of this problem is absence of management strategies which were veiled by IT panacea. In order to overcome this problem, this study looks into the internal and external environment change which are surrounded by special libraries. And also examined procedures and method of environment analysis which is needed to build management strategies. As the result of research, this study analyze internal and external environment by SWOT analysis method, and finally propose new management strategies.