• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.59 no.1
• /
• pp.197-203
• /
• 2010

The problem of location awareness in wireless sensor networks where nodes use GPS (Global Positioning System), remains challenging problem, when considering the required large energy consumption during the localization phase. In this paper we designed hardware for GPS based localization and propose a framework, called ELS, to consume low cost energy. In the ELS framework, sensor nodes are equipped with GPS. Because GPS spends large energy for position awareness, conventional localization algorithms cannot use GPS-device. We try to find a solution for efficient energy expenditure of GPS. Finally, we derive optimal transmission power of GPS data and a scheme of localization through experiment and simulation.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 2007.11a
• /
• pp.464-468
• /
• 2007

In cognitive radio systems, secondary users, unlicensed users, can use primary users' spectrum to increase spectrum efficiency. At that time, the systems must satisfy primary users' QoS. When secondary users use cognitive radio systems, secondary users communication can be terminated, because of satisfying primary users' QoS. However, secondary users' communication terminating is not good for both secondary users and whole systems. So, cognitive radio systems need an efficient algorithm for secondary users of admission control and keeping connections. In this paper, we present an algorithm which consist of two part, admission control and connections control.

• Journal of Korea Technology Innovation Society
• /
• v.2 no.3
• /
• pp.107-117
• /
• 1999

This study was conducted to provide a improving direction of R&D investment for agricultural technology. The results is summerized as follows : 1) it is necessary to make a systematic master-plant of R&D investment for agricultural technology especially including management system 2) Reinforcement of researchers and investment related with agricultural technology might be im-portant factor 3) To clarify the roles by organization is necessary to efficient management for this is needed to efficient use of research resource 5) In the meeting pro-vice era a synthetic management of tech-nology developed by researchers and mutual exchange between research organization researcher is necessary. Finally Builing up a information delivery system of agricultural technology compatible to use the technology developed is recommended.

• Smart Structures and Systems
• /
• v.8 no.1
• /
• pp.107-117
• /
• 2011

Biological sensory systems continuously monitor and analyze changes in real-world environments that are relevant to an animal's specific behavioral needs and goals. Understanding the sensory mechanisms and information processing principles that biological systems utilize for efficient sensory data acquisition may provide useful guidance for the design of smart-sensing systems in engineering applications. Weakly electric fish, which use self-generated electrical energy to actively sense their environment, provide an excellent model system for studying biological principles of sensory data acquisition. The electrosensory system enables these fish to hunt and navigate at night without the use of visual cues. To achieve reliable, real-time task performance, the electrosensory system implements a number of smart sensing strategies, including efficient stimulus encoding, multi-scale virtual sensor arrays, task-dependent filtering and online subtraction of sensory expectation.

• Knowledge Management Research
• /
• v.13 no.3
• /
• pp.55-77
• /
• 2012

Selecting promising technology is becoming more and more difficult due to the increased number and complexity. In this study, we propose hybrid AHP/DEA-AR method and hybrid AHP/DEA-AR-G method to evaluate efficiency of technology alternatives based on ordinal rating data collected through survey to technology experts in a certain field and select efficient technology alternative as promising technology. The proposed method normalizes rating data and uses AHP to derive weights to improve the credibility of analysis, then in order to avoid basic DEA models' problems, use DEA-AR and DEA-AR-G to evaluate efficiency of technology alternatives. In this study, we applied the proposed methods to clean technology and compared with the basic DEA models. According to the result of the comparison, we can find that the both proposed methods are excellent in confirming most efficient technology, and hybrid AHP/DEA-AR method is much easier to use in the process of technology selection.

• Proceedings of the KIEE Conference
• /
• 2000.07a
• /
• pp.75-79
• /
• 2000

This paper proposes the optimal placement with minimum set of Phasor Measurement Units (PMU's) using tabu search and makes an alternative plan to secure the robustness of the network with PMU's. The optimal PMU Placement (OPP) problem is generally expressed as a combinatorial optimization problem subjected to the observability constraints. Thus, it is necessary to make a use of an efficient method in solving the OPP problem. In this paper, a tabu search based approach to solve efficiently this OPP problem proposed. The observability of the network with PMU's is fragile at any single PMU contingency. To overcome the fragility, an alternative scheme that makes efficient use of the existing measurement system in power system state estimation proposed. The performance of the proposed approach and the alternative scheme is evaluated with IEEE sample systems.

• The Korean Journal of Air & Space Law and Policy
• /
• v.9
• /
• pp.421-433
• /
• 1997

The orbit and frequency spectrum allocation for the communication and broadcasting satellite services are coordinated between the concerned parties according to the Radio Regulations of International Telecommunication Union (ITU). Currently, the geostationary orbit is filled with too many satellites for the commercial or military uses. In addition, a number of near earth satellite programs are being introduced. As each country claims for the space orbit and spectrum, the limited space resources are being exhausted. In this paper, the current situations in the worldwide satellite orbit demand are discussed, and some ideas on the peaceful, efficient and equitable use of space resources are proposed.

• Proceedings of the IEEK Conference
• /
• 2002.07b
• /
• pp.1176-1179
• /
• 2002

This paper presents the use of a Genetic Algorithm to find the optimal layout for the placement of garment patterns on a fabric of fixed width to minimize fabric waste. We developed a program to simulate garment pieces and their layout on a fixed-width fabric. Each piece in the order book is placed with 2 possible orientations: 0 degrees and 180 degrees. The efficiency is measured by the length of fabric used after all the patterns in the order book have been laid out. A comparison is made between the placement using our proposed genetic algorithm to that made by an expert human using our simulation program. The results from our experiments on various pattern designs indicate that our genetic algorithm can effectively be used to obtain highly efficient solutions, comparable to that done by an expert while using a reasonable amount of time. The algorithm can also be adapted for use in other areas related to optimal consumption of sheet material such as metal, paper, and leather.

• Computers and Concrete
• /
• v.5 no.5
• /
• pp.449-459
• /
• 2008

This paper focuses on the application of two dimensional orthogonal polynomials in the regression analysis for the relationship of product parameters viz. compressive strength, bulk density and water absorption of fly ash cement bricks with other process parameters such as percentages of fly ash, sand and cement. The method has been validated by linear and non-linear two parameter regression models. The use of two dimensional orthogonal system makes the analysis computationally efficient, simple and straight forward. Corresponding co-efficient of determination and F-test are also reported to show the efficacy and reliability of the relationships. By applying the evolved relationships, the product parameters of fly ash cement bricks may be approximated for the use in construction sectors.

• Proceedings of the KSR Conference
• /
• 2010.06a
• /
• pp.756-761
• /
• 2010

Bimodal trams are run by a guidance system and combine the functions of buses and trains. The trams have been highlighted as an alternative means of public transportation due to their accessibility, mobility, and arrival accuracy. While bimodal trams can be implemented on existing roads or by road expansion, with the narrow road conditions in Korea, studies must be performed in advance on suitable lane and platform locations and the exclusivity of lane use. This paper proposes plans for the location of bimodal tram lanes and platforms, whether in the median or at the road’s edge. In addition, methods of efficient bimodal tram operation are discussed, including the implementation of exclusive tram lanes.