• Journal of the Korea Society of Computer and Information
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• v.20 no.4
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• pp.77-85
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• 2015

Recently, wireless sensor network(WSN) have been used in various fields to implement ubiquitous computing environment. WSN uses small, low cost and low power sensors in order to collect information from the sensor field. This paper proposes a clustering algorithm for energy efficiency of sensor nodes. The proposed algorithm is based on conventional LEACH, the representative clustering protocol for WSN and it prolongs network and nodes life time using sleep technique and changable transmission mode. The nodes of the proposed algorithm first calculate their clustering participation value based on the distance to the neighbor nodes. The nodes located in high density area will have clustering participation value and it can turn to sleep mode. Besides, proposed algorithm can change transmission method from conventional single-hop transmission to multi-hop transmission according to the energy level of cluster head. Simulation results show that the proposed clustering algorithm outperforms conventional LEACH, especially non-uniformly deployed network.

• Journal of Internet Computing and Services
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• v.4 no.4
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• pp.15-25
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• 2003

Wireless ad-hoc networks are only composed with mobile devices. Unlike the traditional wired networks, those devices are mostly operated with battery power. Since the battery-operated power is limited, the efficient energy resource managements becomes an important issue in wireless ad-hoc networks and various studies that considered these characteristics are progressed. One of those studies is an energy efficient routing using coordinators. In this method. only devices elected as coordinator participate in data transmissions in ad-hoc networks, while other devices remain in sleep node. The overall energy consumption of a system can be reduced. In order to minimize energy consumption of a total network, previous results try to maximize the number of nodes in sleep mode. However, minimizing the number of coordinators does not ensure to increase the system lifetime. In this thesis, we propose an algorithm that can elect coordinators with considering the amount of necessary energy to transmit assigned data and a connectivity of nodes in the networks. The result of proposed coordinator election algorithm can increase the system lifetime of an Ad-hoc network from the results of existing coordinator election algorithms.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.1
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• pp.9-21
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• 2016

Nowadays various methods for energy saving have been studied in IP networks. This paper suggests a 2-phase OSPF routing method for energy saving on IP networks having various energy profiles and analyzes its characteristics. The phase-1 of the routing is an OSPF routing method considering the energy cost of devices besides existing metrics to minimize energy consumption. In the phase-2 of the routing, it makes core nodes go into sleep sate for energy saving and reroutes the paths affected by sleeping core nodes. At this time, we confirm that the characteristics of mean delay and energy efficiency can be satisfied by limiting an allowable hop number in the reroute paths, and utilization rate of nodes and links for assuring energy saving and network-level QoS. Since the efficiency of energy saving and delay characteristics differ according to selection methods of core nodes to go into sleep state, it is that the a method of core node selection based on MP(minimum_path) is more excellent than others in terms of network-level QoS and energy saving in IP networks.

• The Journal of the Korea Contents Association
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• v.12 no.8
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• pp.69-76
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• 2012

This paper proposes an efficient power consumption scheme using sleep mode in home gateway. The scheme by this paper classifies incoming real time packet and non-real time packet in home gateway and delay non-real time packet. Therefore, the home gateway can have longer sleep time because non-real time packet can get additional delay time by proposing mechanism using timer. We use non-preemptive two priority queueing model for performance analysis. As a results, we verify that power consumption of proposed scheme is reduced more than existing scheme by delay of non-real time traffic.

• Convergence Security Journal
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• v.13 no.4
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• pp.27-32
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• 2013

In this paper, technologies applied to design urination detection device on diaper that issues an alarm signal to guardian within 10~20m are introduced. It features power saving that uses both low power bluetooth v4.0 chip and low-power program scheme that makes sensor and mirco-controller to be sleep mode while data is not receiving from sensor. Urination detection algorithm that utilizes the difference between previous sensing data and current values is used to improve the degree of the detection precision level. The device designed with the suggested technologies shows the performance that is 100ml of the minimum urine amount for detection, more than 90% of urination detection degree, and 100% of wireless communication success rate.

• KIPS Transactions on Computer and Communication Systems
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• v.3 no.11
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• pp.393-402
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• 2014

We have experienced an explosive increase of the IoT(Internet of Things) technology based devices including smart phones and the wireless communications. Also the growing power consumption in IEEE 802.11 WLANs(Wireless LANs) driven by these dramatic increases in not only mobile users and but also wireless APs(Access Points). To reduce the power consumption, this paper proposes a wireless AP power saving algorithm, which minimizes the transmission power without decrease the transmission and carrier sense ranges. A wireless AP which is use in our algorithm checks its own original coverage periodically for whether there is a new STA(Station) or not when its transmission power is decreased. Moreover, if there are no signaling message to connect the wireless AP, it changes its operation mode Wake-up to sleep. A Result shows that the proposed AP algorithm can reduce the total power consumption of the wireless AP approximated 18% and 35% compared to the conventional wireless AP with and without the existing power saving algorithm, respectively.

• Fire Science and Engineering
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• v.26 no.1
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• pp.74-79
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• 2012

This study is described for development of the stand-alone smoke and heat detector (SASHD) according to the revised in 2011 type approval and performance inspection code for detector. The main improvement of the revised regulation is source. CMOS microcontroller with nano watt technology is use for development of the workable SASHD over 10 years. The low-power SASHD is developed by using the power-saving sleep mode of microcontroller, by making the low-power source voltage checker, heat detector and smoke detector. The stand-alone detector is developed by smoke and heat detector type for reduce false fire alarm. User can choose type of work between the heat detection mode and smoke & heat detection mode. The SASHD can communicate with each them using RS-485 communication supported from microcontroller. So, this study can develop the SASHD that is able to alarm more wide area when fire occurs and reduce a flash fire alarm.

• Proceedings of the Korea Information Processing Society Conference
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• 2010.11a
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• pp.1711-1713
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• 2010

본 논문에서는 다수의 PC를 사용하는 네트워크 환경에서 사용자의 사용이 끝난 PC에 대해 전력을 관리함으로써, 불필요한 전력의 낭비를 절감하여 에너지의 효율을 높일 수 있는 다수의 PC 전력 제어 시스템을 제안한다. 현재의 PC의 전력을 관리하기 위한 방법으로는 Microsoft Windows나 Linux 등의 OS에서 기본적으로 절전 모드를 제공한다. 그러나 전력을 차단하는 것만큼 불필요한 에너지를 절감할 수 있는 방안은 없다. 따라서 본 논문에서는 이러한 불필요한 에너지들을 절감하기 위하여 네트워크를 기반으로 구축된 PC 환경에서, 전력의 유무를 검사하고 불필요한 전력을 차단할 수 있는 방안을 제시한다. 결과적으로 제안한 방법을 통하여 다수의 PC를 사용하는 환경에서 불필요한 전력을 감지하여, 이를 차단함으로써 에너지의 효율을 극대화 할 수 있었다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.1
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• pp.177-182
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• 2014

In this paper, we propose an energy efficient sink node based MAC protocol for Wireless Sensor Networks (WSNs). The proposed sink node-based MAC (SB-MAC) protocol uses a RB(rapid beacon) frame to save sender's energy consumption and to reduce transmission delay. The RB frame is a modified IEEE 802.15.4 beacon frame. The RB frame contains the length of the sender nodes data. Using this information other nodes except sender and receiver nodes can be stay sleep mode long time to reduce energy consumption. Results have shown that the SB-MAC protocol outperformed other protocols like X-MAC and RI-MAC in terms of packet delivery delay and energy consumption. The SB-MAC protocol is especially energy efficient for the networks with one sink node and many senders.

• Journal of the Korea Society of Computer and Information
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• v.16 no.4
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• pp.119-126
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• 2011

When ZigBee network supports beacon transmission mechanism, ZigBee devices have the restriction of the transmission range from the coordinator. On the contrary, when it does not support beacon transmission, it is not easy to save the energy through turning into sleep mode. This paper proposes active slot allocation method that allocates a transmission time and does not use the beacon transmission mechanism. It is based on the ZigBee's distributed address assignment mechanism and supports the scalability. This paper explains the active slot structure and the allocation order and describes the operation of ZigBee devices. We verify the proposed mechanism through the simulation and show the performance evaluation. It can be useful on the industrial automation and the environmental surveillance.