• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.7 no.2
• /
• pp.234-252
• /
• 2013

Due to the uncertain of connections in Delay Tolerant Networks (DTNs), most routing algorithms in DTNs need nodes to forward the message to others based on the opportunistic contact. The contact is related with the beaconing rate. In particular, nodes have more chances to encounter with each other with bigger beaconing rate, but more energy will be used. On the other hand, if the nodes forward the message to every node all the time, the efficiency of the routing algorithm is better, but it needs more energy, too. This paper tries to exploit the optimal beaconing rate and forwarding rate when the total energy is constraint. First, a theoretical framework is proposed, which can be used to evaluate the performance with different forwarding rate and beaconing rate. Then, this paper formulates a joint optimization problem based on the framework. Through Pontryagin's Maximal Principle, this paper obtains the optimal policy and proves that both the optimal forwarding and beaconing rates conform to threshold form. Simulation results show the accuracy of the theoretical framework. Extensive numerical results show that the optimal policy obtained in this paper is the best.

• Journal of Korean Society for Quality Management
• /
• v.44 no.2
• /
• pp.277-296
• /
• 2016

Purpose: Propose model to diagnose and assess National Defense Industry and quality management by investigating and analyzing established standard model. Methods: Research on established internal model including MB, EQA and JQA model and make standard index for quality index extraction and quantitative index to test objectively for internal state. Results: Extract advantage and disadvantage by performance of National Defense Industry level diagnose and build foundation for quality management policy and road map. Conclusion: Due to result of diagnostic assesment of quality management of national defense industry, dependability, SCQM and safety part shows vulnerability and require improvement and support.

• IE interfaces
• /
• v.21 no.3
• /
• pp.254-261
• /
• 2008

Connected-(r,s)-out of-(m,n) : F system is an important topic in redundancy design of the complex system reliability and it's maintenance policy. Previous studies applied Monte Carlo simulation and genetic, simulated annealing algorithms to tackle the difficulty of maintenance policy problem. These algorithms suggested most suitable maintenance cycle to optimize maintenance pattern of connected-(r,s)-out of-(m,n) : F system. However, genetic algorithm is required long execution time relatively and simulated annealing has improved computational time but rather poor solutions. In this paper, we propose the ant colony optimization approach for connected-(r,s)-out of-(m,n) : F system that determines maintenance cycle and minimum unit cost. Computational results prove that ant colony optimization algorithm is superior to genetic algorithm, simulated annealing and tabu search in both execution time and quality of solution.

• Journal of the military operations research society of Korea
• /
• v.17 no.1
• /
• pp.43-60
• /
• 1991

Consider N queues without arrivals and with m identical servers. All jobs are independent and service requirements of jobs in a queue are i.i.d. random variables. At any time only one server may be assigned to a queue and switching between queues are allowed. A unit cost is imposed per job per unit time. The objective is to minimized the expected total cost. An flow approximation model is considered and an upperbound for the percentage error of best nonswitching policies to an optimal policy is found. It is shown that the best nonswitching policy is not worse than $11\%$ of an optimal policy For the stochastic model, we consider the case in which the service requirements of all jobs are i.i.d. with an exponential distribution. A longest first policy is shown to be optimal and a worst case analysis shows that the nonswitching policy which starts with the longest queues is not worse than $11\%$ of the optimal policy.

• Industry Promotion Research
• /
• v.5 no.4
• /
• pp.15-28
• /
• 2020

In this study, the methodology for measuring the structure of the Korean defense market and the competition status, and the characteristics of the Korean defense industry and the market are examined. To analyze the structure of the Korean defense market and the competition status, the market share, concentration ratio, and the Herfindal-Hirschman index are employed based on the annual sales of major Korean defense companies. On a basis of the result of the analysis, the suggestions for the Korean defense market to escape from the monopolistic market to be a competitive geographical market are presented. To present the suggestions, markets that have a similarity with the dense market are analyzed. The government's support policy, the selection of the companies led by the government, and the cost of the military are suggested for the defense market on a basis of analyzing similar markets. With the suggestions, when the government pursues the policies, the defense market sticking to principles and fairness is created and the efficiency of the companies operation is achieved, by enhancing the structure of the market fundamentally and the development of the policies in the industry's perspective.

• Defense and Technology
• /
• no.8 s.198
• /
• pp.20-31
• /
• 1995

프랑스는 Georges Pompidou 대통령시절인 1972년, 식민지의 독립화 및 근대화로 전환되는 과정에서 De Gaulle장군의 국방원칙을 수용한 최초의 국방백서를 발간했으며, 22년만인 1994년에 베를린장벽의 붕괴 및 Warsaw Pact의 해체에 따른 유럽내의 급격한 변화, 국제환경여건, 과학기술 발전 및 현대경제에 부합되는 새로운 국방백서를 발간하였다. 이번에 발간한 국방백서는 총 3부로 1부는 , 2부는 , 3부는 로 되어있다. 여기에 소개하는 방위산업 분야는 3부 7장의 를 번역정리한 것으로 관계 분야 종사자들에게 조금이나마 도움이 되기를 바란다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2000.06a
• /
• pp.97-97
• /
• 2000

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2013.04a
• /
• pp.859-860
• /
• 2013

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.12
• /
• pp.8378-8385
• /
• 2015

The interest of global competitiveness for national defense industry. This study analyzes the efficiency and productivity of 45 defense companies in each continent(North America, Europe and Northeast Asia, etc.), including Korea defense companies. It is analyzed by Data Envelopment Analysis(DEA) and Malmquist Productivity Analysis over the period 2009-2013(5 years). The sample companies has been selected on the data avilability among the SIPRI Top 100 arms-producing and military services companies in the world(excluding China) in 2013. It extracts the relative efficiency and Malmquist productivity index of companies and each continent. Based on the DEA and MPI results, this paper estimates the global competitiveness and position of national defense industry and extracts implication. This study can be utilized for improvement of national defense industry and policy planning for cultivating the national defense companies.

• Convergence Security Journal
• /
• v.19 no.4
• /
• pp.3-12
• /
• 2019

The outflow of defense technology can cause serious damage not only in terms of business losses, but also in terms of national security and national interests. Recently, the government has enacted the Defense Technology Security Act, recognizing the importance of technology in the defense industry, and prepared guidelines for the defense technology security accordingly. According to the law, institutions and companies with defense technologies should establish a defense technology protection system, and the government should implement various technology protection policies to improve their level of technology protection. In this study, the implications were derived by comparing existing technology protection guidelines and priority analysis was performed on the protection system details through AHP for self-diagnosis items in the defense technology security guidelines. As a result, it is expected that it will enable efficient diagnosis of the level of protection and policy support for the systematic establishment of the protection system for the target institutions.