• International Journal of Computer Science & Network Security
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• v.23 no.7
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• pp.109-118
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• 2023

Energy awareness is an essential design flaw in wireless sensor network. Clustering is the most highly regarded energy-efficient technique that offers various benefits such as energy efficiency and network lifetime. Clusters create hierarchical WSNs that introduce the efficient use of limited sensor node resources and thus enhance the life of the network. The goal of this paper is to provide an analysis of the various energy efficient clustering algorithms. Analysis is based on the energy efficiency and network lifetime. This review paper provides an analysis of different energy-efficient clustering algorithms for WSNs.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.10.1-10.1
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• 2011

Energy harvesting technologies converting external sources (such as thermal energy, vibration and mechanical energy from the nature sources of wind, waves or animal movements) into electrical energy is recently a highly demanding issue in the materials science community for making sustainable green environments. In particular, fabrication of usable nanogenerator attract the attention of many researchers because it can scavenge even the biomechanical energy inside the human body (such as heart beat, blood flow, muscle stretching, or eye blinking) by converging harvesting technology with implantable bio-devices. Herein, we describe procedure suitable for generating and printing a lead-free microstructured $BaTiO_3$ thin film nanogenerator on plastic substrates to overcome limitations appeared in conventional flexible ferroelectric devices. Flexible $BaTiO_3$ thin film nanogenerator was fabricated and the piezoelectric properties and mechanically stability of ferroelectric devices were characterized. From the results, we demonstrate the highly efficient and stable performance of $BaTiO_3$ thin film nanogenerator and the integration of bio-eco-compatible ferroelectric materials may enable innovative opportunities for artificial skin and energy harvesting system.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.11a
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• pp.291-294
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• 2007

Countries in the world are setting up policies to implement anti-global warning measures to actively cope with the Agreement on Climate Change. Rising problems related to energy and environment prompted research and development efforts to highly efficient electric instrument and environmentally friendly products to secure resources and save energy Korea's high dependency on imported energy and its lack in natural resources make it urgently necessary to develop energy efficient instrument and equipment that can save energy. Every household now uses a transformer, which is very important instrument among others. A variety of technologies to manufacture transformers are currently used along with efforts to develop new materials. Development nit of high efficient transformers is called for by the time and has direct economic impact on suppliers and consumers. In addition, it is desirable to install a transformer that is trustworthy, secure, low on loss, anti-incident capable, small, anti-flammable, environmentally friendly, cost-efficient high-frequency resistant and easy for maintenance. To do this, it is necessary to look deeper into a highly efficient transformer that can save energy. This paper will discuss the types and characteristics of various transformers and propose ways to save energy and raise efficiency tv analyzing a environmentally friendly amorphous transformer.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.2B no.3
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• pp.100-108
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• 2002

A simple sustain driver employing an energy recovery function is proposed as a highly efficient driver of a plasma display panel. The proposed driver uses dual resonance in the sustaining mode operation: a main resonance between an inductor and an external capacitor to produce alternative pulses and a sub-resonance between an inductor and a panel to recover the energy consumption by the capacitive displacement current of the PDP. The operational principle and design procedure of the proposed circuit are presented with theoretical analysis. The operation of the proposed sustain driver is verified through simulation and experiments based on a 7.5-inch-diagonal panel with a 200 KHz operating frequency.

• Explosives and Blasting
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• v.27 no.2
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• pp.56-60
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• 2009

In view of physics, energy is defined as the ability to work. The use of natural gas and nuclear power have been increased since 1980s to replace fossil fuels such as coal and petroleum. Recently, solar energy, wind power, tidal power, and geothermal energy have been considered as promising alternative energy sources to overcome environmental pollution. However, their energy efficiencies are much lower than those of chemical energies such as nuclear power, explosive, and petroleum gas. In this study, the present situation of the green energy was reviewed to seek out the way to overcome the limit of the environmental (alternative) energy. Also, purification, application and development trend of the highly efficient alternative energy sources were investigated.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1516-1519
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• 2008

We report extremely low doping technology in phosphorescent organic light emitting diodes(PHOLEDs). Highly efficient red PHOLEDs with excellent energy transfer characteristics even under 1 % doping condition have been demonstrated. Results reveal efficient host-dopant system to realize highly efficient PHOLEDs and useful cost saving way by reduction of expensive Ir complex dopants.

• Journal of Applied Reliability
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• v.11 no.1
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• pp.83-95
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• 2011

Boiler efficiency has a direct impact on energy consumptions, which results in lower cost of operations and services. Usually high efficiency boilers are regarded as boilers with an efficiency of greater than 90%. However, it is likely that normal boilers are running at significantly lower efficiencies than this. This paper presents a process of developing a highly efficient energy consumption boiler. We adopt direct heat method while normal boilers are designed as indirect heat method. The submerged combustion method is considered to design for very high efficient boiler.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.9B
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• pp.792-802
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• 2006

In this paper, we propose an energy-efficient proactive data dissemination protocol with relatively low delay to cope well with highly mobile sink environments in sensor networks. In order for a dissemination tree to continuously pursue a dynamic sink, we exploit two novel algorithms: forward sink advertisement and distributed fast recovery. In our protocol, the tree is shared with the other slave sinks so that we call it Dynamic Shared Tree (DST) protocol. DST can conserve considerable amount of energy despite maintaining robust connection from all sources to sinks, since tree maintenance of DST is accomplished by just distributed local exchanges. In addition, since the DST is a kindof sink-oriented tree, each source on the DST disseminates data with lower delay along the tree and it also facilitates in-network processing. Through simulations, it is shown that the presented DST is considerably energy-efficient, robust protocol with low delay compared to Directed Diffusion, TTDD, and SEAD, in highly mobile sink environment.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.946-951
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• 2009

The research aims to study a new, optimum and renewable energy application method that can cover the minimum energy and operation costs within a range of school budgets. By deriving the optimum application method, it is expected to maximize the cooling/heating and water heating energy saving efficiencies for educational facilities. Therefore, this research carried out a study on the new/renewable energy utilization technique diffusion expansion method and the optimum method. As a result, the first optimum plan was introduced with the multi-type geothermal heat pump 174kW + solar heat collector $94\;m^2$ + highly efficient electronic cooling/heating device (EHP) 249.4kW. On the other hand, the second optimum plan was induced as the multi-type geothermal heat pump 255.2kW + highly efficient electronic cooling/heating device (EHP) 168.2kW.

• Journal of Information Display
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• v.10 no.2
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• pp.87-91
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• 2009

Highly efficient red phosphorescent OLEDs (PHOLEDs) with a simple, organic, triple-layer structure was developed using the narrow-bandgap fluorescent host material bis(10-hydroxybenzo[h] quinolinato)beryllium complex (Bebq2) and the deep-red dopant tris(1-phenylisoquinoline)iridium (Ir(piq)3). The maximum current and power efficiency values of 12.71 cd/A and 16.02 lm/W, respectively, with an extremely low doping technology of 1%, are demonstrated herein. The results reveal a practical, cost-saving host dopant system for the fabrication of highly efficient PHOLEDs involving the simple structure presented herein, with a reduction of expensive Ir dopants.