• Journal of Information Processing Systems
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• 제1권1호
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• pp.49-54
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• 2005

With the recent advances in Micro Electro Mechanical System (MEMS) technology, low cost and low power consumption wireless micro sensor nodes have become available. However, energy-efficient routing is one of the most important key technologies in wireless sensor networks as sensor nodes are highly energy-constrained. Therefore, many researchers have proposed routing protocols for sensor networks, especially cluster-based routing protocols, which have many advantages such as reduced control messages, bandwidth re-usability, and improved power control. Some protocols use information on the locations of sensor nodes to construct clusters efficiently. However, it is rare that all sensor nodes know their positions. In this article, we propose another cluster-based routing protocol for sensor networks. This protocol does not use information concerning the locations of sensor nodes, but uses the remaining energy of sensor networks and the desirable number of cluster heads according to the circumstances of the sensor networks. From performance simulation, we found that the proposed protocol shows better performance than the low-energy adaptive clustering hierarchy (LEACH).

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권1호
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• pp.114-130
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• 2021

With the drastic growth of Information and Communication Technology (ICT) industry, global energy consumption is exponentially increased by mobile communications. The huge energy consumption and increased environmental awareness have triggered great interests on the research of dynamic distribution of cell user and traffic, and then designing the energy efficient cellular network. In this paper, we explore the temporal and spatial characteristics of human mobility and traffic distribution using real data set. The analysis results of cell traffic illustrate the tidal effect in temporal and spatial dimensions and obvious periodic characteristics which can be used to design Base Station (BS) dynamic with sleeping or shut-down strategy. At the same time, we designed a new Cell Zooming and BS cooperation mode. Through simulation experiments, we found that running in this mode can save about 35% of energy consumption and guarantee the required quality of service.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2008년도 추계학술발표대회 논문집
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• pp.141-146
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• 2008

For the efficient use of thermal energy and its related equipments, optimal energy in view of quality and quantity should be timely provided. The core of thermal energy storage technology deals with an energy efficiency for effective energy storage and supply. The relative importance of thermal energy storage technology has been underestimated so far, and the specific projects on this filed have been performed intermittently. For the efficient and systematic approach of the energy supply system projects on thermal energy storage technology, we conduct the survey on the current status of this field. Firstly, classify into the thermal energy storage and describing the recent research for each system. The necessity and importance of thermal energy storage technology is identified through this study. It reveals that the thermal energy storage is the mandatory technology to solve the difference of supply and demand in thermal loads. It would greatly contribute to the combined heat and power(CHP) system. The urgent technologies for the commercial value and the core technologies for the CHP system are classified with this study.

• Journal of Information Processing Systems
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• 제6권3호
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• pp.269-294
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• 2010

The interconnection of mobile devices in urban environments can open up a lot of vistas for collaboration and content-based services. This will require setting up of a network in an urban environment which not only provides the necessary services to the user but also ensures that the network is secure and energy efficient. In this paper, we propose a secure, energy efficient dynamic routing protocol for heterogeneous wireless sensor networks in urban environments. A decision is made by every node based on various parameters like longevity, distance, battery power which measure the node and link quality to decide the next hop in the route. This ensures that the total load is distributed evenly while conserving the energy of battery-constrained nodes. The protocol also maintains a trusted population for each node through Dynamic Trust Factor (DTF) which ensures secure communication in the environment by gradually isolating the malicious nodes. The results obtained show that the proposed protocol when compared with another energy efficient protocol (MMBCR) and a widely accepted protocol (DSR) gives far better results in terms of energy efficiency. Similarly, it also outdoes a secure protocol (QDV) when it comes to detecting malicious nodes in the network.

• 한국통신학회논문지
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• 제32권7B호
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• pp.411-421
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• 2007

무선 센서 네트워크에서 가장 큰 문제 중의 한 가지는 네트워크를 구성함에 있어 에너지 소모를 최소화하는데 있다. 센서 네트워크에서 에너지를 효율적으로 사용하기 위해서 주로 다음과 같은 두 종류의 방식을 사용한다. 한 가지는 동적 전력 관리를 사용하는 것이며, 다른 한 가지는 에너지 효율적인 프로토콜을 사용하는 것이다. 전자의 경우 전원 관리자는 해당하는 이벤트들에 대해서 CPU와 해당 I/O들의 적절한 전원 상태를 관리할 책임이 있다. 하지만, 주어진 프로토콜의 내부 동작에 대해서는 관여하지 못한다. 그것은 충돌 등으로 인한 통신 상태에서의 지연에 의한 불필요한 에너지를 낭비할 가능성이 크다. 반면에 에너지 효율적인 프로토콜들은 단지 무선 모뎀의 전원 상태만을 고려한다. 본 논문에서 우리는 통신 이벤트 기반의 전력 관리를 통한 무선 센서 노드들의 불필요한 전력 소비를 충분히 줄일 수 있는 에너지 효율적인 전력 관리 방안을 제안하고, 시뮬레이션을 통해 제안하는 전력 관리 방식이 상당한 에너지를 절약 할 수 있음을 보인다.

• 인터넷정보학회논문지
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• 제23권5호
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• pp.1-7
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• 2022

무선 인체 영역 네트워크(WBAN)와 바이오센서를 활용하는 IoT기술은 자원을 최소화 하고 환자를 모니터링 하는 보건산업에서 중요한 분야이다. IoT와 WBAN을 보다 효율적으로 통합하기 위해서는 WBAN의 제한된 자원 센서노드와 효율적인 데이터 전송을 위한 신속 정확한 라우팅을 구성하는 협력 프로토콜이 필요하다. 본 논문은 중복 데이터 전송감지, 제한된 네트워크 센서의 수명연장 문제를 해결하기 위해 에너지 효율적이고 협력이 가능한 링크 에너지 효율적인 라우팅 전략(LEERS)을 제안한다. 제안된 기법은 잔류에너지 싱크쪽으로 가는 홉수 노드 혼잡 수준 및 대역폭과 효율적인 매개변수를 고려한다. 또한 노드의 경로비용함수를 결정하고 효과적인 멀티홉 라우팅을 제공함으로서 잔류에너지와 처리량 측면에서 효율성이 향상됨을 보인다.

• International Journal of Advanced Culture Technology
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• 제1권2호
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• pp.18-23
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• 2013

In this paper, we consider the problem of designing optimal sensing time and the minimization of energy consumption in the Cognitive radio Network. Trade-off between throughput and the sensing time are observed, and the equations are derived for the optimal choice of design variables. In this paper, we also look at the optimization problem involving all the design parameters together. The advantages of the proposed scheme for the spectrum sensing and access process are shown through simulation.

• 한국신뢰성학회지:신뢰성응용연구
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• 제11권1호
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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.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2000년도 학술대회논문집
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• pp.235-240
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• 2000

This paper presents the reasonable method for electric power management through efficient use of electricity. With a rapid of national economics and living standard, electrical energy consumption markedly increased. Especially it is increased electrical energy consumption in commercial buildings and thus an energy conservation through efficient use of electricity became more important.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2011년도 춘계학술발표대회
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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.