• 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.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2011.07a
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• pp.105-107
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• 2011

본 논문에서는 모바일 디바이스에서 영상 서비스와 같이 지연에 민감한 서비스를 이용할 때 적합한 절전 모드(psm) 파라미터를 제안한다. 휴대기기의 특성상 전력에 제한이 있는 모바일 디바이스라는 관점에서는 전력 소모가 중요한 문제인데 지연에 민감한 영상 서비스의 관점에서는 절전 모드에 동반되는 응답지연 또한 매우 중요한 문제이다. 따라서 영상 서비스와 같이 지연에 민감한 서비스를 이용할 때에 단순히 소비 전력을 최소화 하는 psm 을 적용해서는 응답지연이 늘어나게 된다. 그렇기 때문에 전력 소모와 응답지연의 trade-off 를 고려한 psm 를 적용하는 것이 필요한데 이를 위해 본 논문에서는 허용 지연에 따른 절전 모드 파라미터를 찾는 방법을 제안하고자 한다.

• Solar Energy
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• v.19 no.3
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• pp.1-11
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• 1999

Previous researchers have studied how to reduce a pumping power in order to save energy in the fluid transporting system. Especially, it has been studied a lot about reducing the pressure drop among parameters related to the energy saving for fluid transport. This study is to investigate the effect of a substantial drag reduction caused by the polymer(A611P, A601P) when the working fluids flow to the vertical and horizontal direction in the vertical cylindrical equipment of closed flow system. In this experiment, we mount a visualization equipment on the test section and take pictures. With using the PIV system, instrument and analyzing the movement of bubble for different polymer concentration are observed and some mechanism of the drag reduction effect is clarified.

• Proceedings of the Korea Information Processing Society Conference
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• 2024.05a
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• pp.154-157
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• 2024

최근 무선랜은 증가하는 트래픽 수요와 사용자의 다양한 애플리케이션 요구사항을 충족하기 위해 표준 기술이 진화하고 있다. 상용화가 본격적으로 시작된 WiFi 7 표준은 더 낮은 지연 시간과 더 높은 스루풋을 달성하기 위해서 멀티링크 동작(Multi-Link Operation, MLO) 기능을 도입하였다. 멀티 링크 동작은 다른 주파수 대역이나 채널을 활용하여 동시에 데이터를 송수신하는 기술로서 스루풋은 증가하지만, 전력 소모량이 커지는 문제가 있다. 또한, 종래의 무선랜 표준 기술들은 대부분 저전력의 경량 단말에서만 에너지 절감을 고려해 왔으며, AP(Access Point)의 에너지 효율성은 고려하지 않았다. 따라서 본 논문에서는 멀티링크 동작을 지원하는 AP에서 에너지 효율을 개선하는 파워 세이빙 메커니즘을 제안한다. 실험 결과에 따르면, 스루풋을 높이기 위해 링크를 산발적으로 사용하는 종래의 방식 대비 제안하는 방식의 에너지 효율성이 최대 19.18% 개선되었다.

• IEMEK Journal of Embedded Systems and Applications
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• v.10 no.4
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• pp.213-219
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• 2015

Real-time energy monitoring systems is a demand-response system which is reported to be effective in saving energy up to 12%. Real-time energy monitoring system is commonly composed of smart-plugs which sense how much electrical power is consumed and IHD(In-Home Display device) which displays power consumption patterns. Even though the monitoring system is effective, users should themselves match which smart plus is connected to which appliance. In order to make the matching work to be automatic, the monitoring system need to have appliance identification algorithm, and some works have made under the name of NILM(Non-Intrusive Load Monitoring). This paper proposed an algorithm which utilizes multiple classifiers to improve accuracy of appliance identification. The algorithm proposes to understand each classifiers performance, that is, when a classifier make a result how much the result is reliable, and utilize it in choosing the final result among result candidates from many classifiers. By using the proposed algorithm this paper make 4.5% of improved accuracy with respect to using single best classifier, and 2.9% of improved accuracy with respect to other method using multiple classifiers, so called CDM(Commitee Decision Mechanism) method.

• Journal of Biosystems Engineering
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• v.36 no.3
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• pp.171-179
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• 2011

Facing the current hikes of labor wage and high oil price, it is needed to have energy-saving machinery which also enables us precise farm operations. Thus, it was necessary to develop a safe machine which allows secure and pleasant works along orchard slopes. In this study, a lifting utility with balance-controlled platform was developed. The platform utility could maintain to level the workbench while driving along slopes. Even the machine body was driven at the tilt angle ranges of ${\pm}20^{\circ}$, the platform bench could be maintained within ${\pm}0.5^{\circ}$ of a gimbal angle. In addition, the machine lifted up to 2.0 m using an electric-hybrid driving mechanism with a low noise. A tandem hybrid power source was developed with a DC 72 V, 100 AH for the Deep-Cycle batteries, charged with 3.5 kW gasoline generator as an auxiliary power source. HST, which is one of the CVT's, was adopted as a transmission device, and a crawer track was used for the safety of the vehicle against tip-over. The maximum lifting height of platform was is 2,500 mm, and the maximum extendable width was 2,900 mm.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.7
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• pp.1-7
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• 2014

A variable displacement vane pump is possible to improve the fuel economy by varying the pump capacity with a vane mechanism according to the engine operating speed range and reducing its driving torque. In general the experimental evaluation of the vane pump for the transmission has been performed mainly not with the vehicle or dynamometer test rig but with component test rig due to the implementation and safety problems. In this paper, in order to evaluate the performance of the developed vane pump as well as the compatibility with other rotary and hydraulic components of the target transmission, the transmission dynamometer based test rig is implemented where the developed pump is built into it and then the variable pump capacity and effect of power reduction are investigated experimentally.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.45 no.3
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• pp.175-183
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• 2008

In wireless sensor networks with ad hoc networking capability, sensor nodes are battery operated and are usually disposable once deployed. As a result, each sensor node senses and communicates with limited energy and, thus, energy efficiency has been studied as a key design factor which determines lifetime of a wireless sensor network, and it is more improved recently by using so-called cross-layer optimization technique. In this paper, we propose and implement a new energy saving mechanism that reduces energy consumption during data collection by controlling transmission power at sensor nodes and then measure its performance in terms of lifetime improvement for the wireless sensor network platform ZigbeX. When every sensor node transmits sensed data to its clusterhead, it controls its transmission power down to as low level as communication is possible, resulting in energy saving. Each sensor node controls its transmission power based on RSSI(Received Signal Strength Indicator) of the packet received from its clusterhead. In other words, the sensor node can save energy by controlling its transmission power down to an appropriate level that its clusterhead safely receives the packet it transmits. According to the repetitive experiment of the proposed scheme on the ZigbeX platform using the packet analyzer developed by us, it is observed that the network lifetime is prolonged by up to 21.9% by saying energy during the data collection occupying most amount of network traffic.

• IEMEK Journal of Embedded Systems and Applications
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• v.12 no.4
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• pp.193-204
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• 2017

Various 3D-stacked DRAMs have been proposed to overcome the memory wall problem. Hybrid Memory Cube (HMC) is a true 3D-stacked DRAM with stacked DRAM layers on top of a logic layer. The logic die is mainly used to implement a memory controller for HMC, and it is connected through a high speed serial link called SerDes with a host that is either a processor or another HMC. In HMC, the serial link is crucial for both performance and power consumption. Therefore, it is important that the link is configured properly so that the required performance should be satisfied while the power consumption is minimized. In this paper, we propose a HMC system model included the high speed serial link to estimate performance accurately. Since the link modeling strictly follows the link flow control mechanism defined in the HMC spec, the actual HMC performance can be estimated accurately with respect to each link configuration. Various simulations are conducted in order to deduce the correlation between the HMC performance and the link configuration with regard to memory utilization. It is confirmed that there is a strong correlation between the achievable maximum performance of HMC and the link configuration in terms of both bandwidth and latency. Therefore, it is possible to find the best link configuration when the required HMC performance is known in advance, and finding the best configuration will lead to significant power saving while the performance requirement is satisfied.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.3
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• pp.1246-1259
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• 2015

Certificate-based signature (CBS) combines the advantages of both public key-based signature and identity-based signature, while saving from the disadvantages of drawbacks in both PKS and IBS. The insecure deployment of CBS under the hostile circumstances usually causes the exposure of signing key to be inescapable. To resist the threat of key leakage, we present a pairing-free key insulated CBS scheme by incorporating the idea of key insulated mechanism and CBS. Our scheme eliminates the costly pairing operations and as a matter of fact outperforms the existing key insulated CBS schemes. It is more suitable for low-power devices. Furthermore, the unforgeability of our scheme has been formally proven to rest on the discrete logarithm assumption in the random oracle model.