• Journal of Convergence Society for SMB
• /
• v.1 no.1
• /
• pp.55-65
• /
• 2011

Due to the rapid advance of IT technologies such as mobile communication, sensor network, wearable computer, and so on, the needs of embedded software has increased. In those domain areas, the development of low-power embedded software is one of critical issues to enhance servicability of the system because almost embedded system depends on battery-based power supply system. Therefore this paper identifies the factors that can reduce the power consumption in embedded software operation, and proposes the method that how to handle the factors in software development process. Even though the existing and general studies about power reduction has been performed with code-based analysis, this analysis approach can lead reworks when the requirement for power consumption was not met. Our proposed techniques will support the power reduction in embedded software development process whenever the code was not developed. Our proposed process for lop-power embedded software development can gives the high quality in power-related serviceability.

• Proceedings of the Korean Information Science Society Conference
• /
• 2012.06d
• /
• pp.109-111
• /
• 2012

본 논문에서는 동적으로 현재화면의 최적밝기 정보를 구해 이 값을 이용하여 LCD 장치를 제어하고, 이를 통해 소모전력을 감소시키는 기법을 제안한다. 논문에서 제안된 기법은 프레임버퍼 이미지를 통해 얻은 현재 화면의 이미지 정보를 분석하여 계산된 현재 화면의 최적의 휘도 정보를 찾고 이 값에 맞는 LCD 장치의 최적 Backlight를 계산하는 과정을 거쳐 얻어진 최종 Backlight 레벨로 LCD의 Backlight를 제어하는 방법으로 소모 전력을 절감하는 기법이다. 이 기법을 적용하여 실험을 통해서 약 10%정도의 개선효과를 보였음을 밝힌다.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2014.11a
• /
• pp.707-710
• /
• 2014

최근 지능형 전력망을 통한 전기요금의 실시간 측정이 가능해지면서 시간별 전력 사용량 및 이에 해당하는 비용 산출이 가능하게 되었다. 이에 따라 전기 요금 절감을 위해서는 매 시간 전력 소모를 체크하고 제한 전력 이상을 사용하지 않아야 한다. 본 논문은 지능형 전력망 사용 빌딩에 유전알고리즘을 이용하여 전력을 효율적으로 제어할 수 있는 알고리즘을 제안한다. 각 시간대별 전력 소모량을 계산하여 제한 전력을 넘는 사용량은 다른 시간대로 분산하고 사용하지 못한 전력은 나머지 연산을 통하여 전력 소모량이 최소인 시간대에 분포시키는 나머지 연산을 적용하였다. 또한 실제 전기 사용량 데이터를 기반으로 제안기법이 시간대별 전력소모량의 편차를 해소하고, 기존 전력 사용 패턴에 비해 전력요금의 절감에 기여할 수 있음을 확인 하였다.

• The KIPS Transactions:PartA
• /
• v.16A no.1
• /
• pp.27-34
• /
• 2009

Recently, power saving with high performance is one of the hot issues in the mobile systems. Various technologies are introduced to achieve low-power processors, which include sub-micron semiconductor fabrication, voltage scaling, speed scaling and etc. In this paper, we introduce a new method that reduces of energy loss at the data cache. Our methods take the benefits in terms of speed and energy loss using selective way precharging of way prediction with concurrent way selecting. By the simulation results, our method achieves 10.2% energy saving compared to the way prediction method, and 56.4% energy saving compared to the common data cache structure.

• Journal of Convergence Society for SMB
• /
• v.2 no.2
• /
• pp.13-19
• /
• 2012

Various quality requirements have increased in developing embedded systems. One of those requirements in mobile embedded system is to reduce energy consumption because of limited power supply. Especially as the complexity of embedded software is increased, the interests of the software energy consumption analysis is also increased. In recent years, some studies has been carried out model-based analysis because it can be able to reflect energy consumption requirements in design phase. In this paper, we proposes a model-based energy analysis technique using SysML parametric diagram. The proposed technique designs software activity model using characteristics of parametric diagram, and then energy consumption value by the execution of the model is derived. Our technique has merit that can perform tradeoffs analysis for energy quality property between different implementations.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.43 no.2 s.344
• /
• pp.60-75
• /
• 2006

The MPEG-21 Multimedia Framework initiative aims to support a wide range of networks and devices in the delivery and consumption of multimedia resources. One of the primary goals of MPEG-21 is universal multimedia access (UMA) through Digital Item Adaptation (DIA), which supports multimedia streaming to heterogeneous devices ensurung the same readability and seamlessness. We pioneer power saving of luminal devices with MPEG-21 DIA, so that the MPEG-21 DIA can also be used to support power saving, even though the framework is not primarily designed for power reduction and only limited power awareness is defined by DIA. We introduce several power-saving techniques conforming to MPEG-21 DIA specifications and show the dependency relation among introduced techniques. We achieve energy savings of up to $66\%$ in hand-held multimedia devices with minor QoS (quality of service) degradation.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.25 no.11
• /
• pp.1596-1602
• /
• 2021

Battery-operated IoT devices in IoT systems require low power consumption. In general, IoT devices enter a sleep state synchronously to reduce power consumption. A problem arises when an IoT device has to handle asynchronous user requests, as the duty cycle must be reduced to enhance response time. In this paper, we propose a new low-power-consumption scheme, called Repetitive Wake-up scheme for IoT systems of asynchronous environments such as indoor lights control. The proposed scheme can reduce power consumption by sending wake-up signals from the smartphone repetitively and by retaining the IoT device in sleep state to the smallest possible duty cycle. In the various environments with IoT devices at home or office space, we showed that the proposed scheme can reduce power consumption by up to five times compared to the existing synchronous interlocking technique.

• KIPS Transactions on Software and Data Engineering
• /
• v.5 no.5
• /
• pp.209-220
• /
• 2016

While the services of mobile devices like smart phone, tablet, and smart watch have been increased and varied, the software embedded into such devices has been also increased in size and functional complexity. Therefore, increasing operation time of mobile devices for serviceability became an important issue due to the limitation of battery power. Recent studies focus on the software development having efficient behavioral patterns because the energy consumption of mobile devices is caused by software behaviors which control the hardware operations. However, it is often difficult to develop the embedded software with considering energy-efficiency and behavior optimization due to the short development cycle of the mobile services in many cases. Therefore, this paper proposes the refactoring techniques for reducing energy consumption, and enables to fulfill the energy requirements during software development and maintenance. We defined energy bad smells with the code patterns that can excessively consume the energy, and our refactoring techniques are to remove these bad smells. We performed some case studies to verify the usefulness of our refactoring techniques.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.34 no.7B
• /
• pp.649-658
• /
• 2009

Due to limited size and limited battery lifetime of sensor node, one has to address the power saving issue in wireless sensor network. The existing power saving algorithm based on data reuse was proposed for the cluster structured wireless sensor network. We state the problem of existing power saving algorithm and propose new power saving algorithm for tree structured wireless sensor network. The proposed algorithm reduces power consumption by buffering the sensed data at the selected relay node for its data lifetime. The optimum buffering node is selected so that the power saving gain is maximized and at the same time, power consumption among sensor nodes are equally distributed in the network. With computer simulations, it is shown that the proposed algorithm outperforms the conventional algorithm in terms of power saving gain.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.34 no.3B
• /
• pp.247-254
• /
• 2009

Over the last decade multiple-input and multiple-output (MIMO) systems have been actively researched and started to be deployed in wireless communications owing to the significant increase in channel capacity. In this paper, we propose a energy saving MAC protocol in systems by focusing on energy efficiency instead of capacity maximization. We considers the energy consumption together with the tradeoff between reliability (i.e., diversity) and throughput (i.e., multiplexing gain), and dynamically chooses an appropriate number of antennas for transmission. In computing the total energy consumption, we counts circuit energy as well as transmission energy. Naturally the circuit energy consumption is directly proportional to the number of active antennas. Through numerical analysis, we confirm that our power saving MAC scheme for MIMO considerably saves energy consumption compared to conventional capacity maximization schemes that use a fixed number of MIMO channels, for a given outage constraint. Our finding is that the capacity maximizing communication which possibly can be regarded best in terms of energy efficiency gives a different solution from the energy minimizing communication.