• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.9 no.4
• /
• pp.792-797
• /
• 2005

Lighting control switches based on the power line communication technology are developed and extended to incorporate dimming control to provide energy saving and appropriate illumination. The developed switch uses a general purpose microprocessor and associated electronics. Both the power line communication and the dimming function are implemented in one microprocessor, and it enables the low price commercialization. The frequency of the carrier was set at 250kHz considering the transmission data length and signal attenuation in power lines. Tests on prototypes in an low-voltage power lines have shown that the switches have a robust operation characteristics with the length of power lines and the variation of load capacities.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.37 no.4
• /
• pp.63-71
• /
• 2014

As power consumption increases, more power utilities are required to satisfy the demand and consequently results in tremendous cost to build the utilities. Another issue in construction of power utilities to meet the peak demand is an inefficiency caused by surplus power during non-peak time. Therefore, most power company considers power demand management with time-based electricity rate policy which applies different rate over time. This paper considers an optimal machine operation problem under the time-based electricity rates. In TOC (Theory of Constraints), the production capacities of all machines are limited to one of the bottleneck machine to minimize the WIP (work in process). In the situation, other machines except the bottleneck are able to stop their operations without any throughput loss of the whole manufacturing line for saving power utility cost. To consider this problem three integer programming models are introduced. The three models include (1) line shutdown, (2) block shutdown, and (3) individual machine shutdown. We demonstrate the effectiveness of the proposed IP models through diverse experiments, by comparing with a TOC-based machine operation planning considered as a current model.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.47 no.10
• /
• pp.27-35
• /
• 2010

In wireless packet networks, energy and wireless resource efficiency is critical issue to addressed for wide deployment. To achieve the both goals of saving the mobile station's energy and increasing the wireless capacity, transmission power control is introduced to wireless packet networks. In the transmission power controled networks, it is not deeply studied on unfairness among transmissions with different power levels that reaches starvation. Through the performance analysis, this paper explains the throughput unfairness of high power transmission with the unfair media access probability owing to the contending node number difference and proposes a simple PHY-MAC cross layer approach.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.15 no.1
• /
• pp.118-124
• /
• 2001

To guide the esti-on of electric d e d and energy saving, this proposed the Power Laaddensity, Elechic pwer consumption and the installed state of Power facility. For this purp~se, it wasconducted a questionnaire survey of the consumption-cattern of Electric power in 1W a p a r t t housings.As a 1-esult it is found that (i) the d m u m value of Power Load density is 7.70[~A/m"l, (ii) the avtragevalue of Power Load dens'||'&'||' is ~ . ~ A / mm' dl (iiijthe average load rate is Ed[%]. Also, the consumptionof electricity one year at tlie whole a m n t s of couniry is 14,0X[GWyearl, it was equivalent to 7[%1 ofthe total-consunmhon of electricity one year at the whole of co1mtnr. co1mtnr.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.24 no.1
• /
• pp.40-48
• /
• 2019

Hybrid electric propulsion systems (H-EPSs) are an intermediate step for integrated full electric propulsion warships. H-EPSs are a dynamic combination of mechanical and electrical propulsion systems to achieve the required mission performances. The system modes could adapt to meet the requirement of the various operation conditions of a warship. This paper presents a configuration and operating modes of H-EPSs considering the operation conditions of a destroyer class warship. The system has three propulsion modes, namely, motoring mode, generating mode [power take off (PTO) mode], and mechanical mode. The PTO mode requires a careful fuel efficiency analysis because the fuel consumption rate of propulsion engines may be low compared with the generator's engines depending on the loading power. Therefore, the calculation of fuel consumption according to the operating modes is performed in this study. Although the economics of the PTO mode depends on system cases, it has an advantage in that it ensures the reliability of electric power in case of blackout or minimum generator operation.

• 제어로봇시스템학회:학술대회논문집
• /
• 2004.08a
• /
• pp.307-311
• /
• 2004

In this study, a novel hybrid vehicle is proposed. The vehicle has a flywheel-engine hybrid system. Flywheels are more effective as energy charge systems than electric batteries in a respect of output power density. However, transmissions to effectively drive flywheels are very complex systems such as CVTs (Continuously Variable Transmissions). In the proposed hybrid vehicle, Constant Pressure System is employed, which is hydraulic power transmission. Using Constant Pressure Systems, hydraulic CVTs are easily realized with variable displacement pumps/motors. In this paper, firstly, the proposed flywheel hybrid vehicle making use of Constant Pressure System is described. Secondly, fuel consumption characteristics of the flywheel hybrid vehicle are experimentally examined with the stationary test facility, which employs a flywheel as a load emulating vehicle inertia. Finally, the experimental results and discussions are described. Fuel consumption of 26km/L is expected for 10 mode driving schedule with vehicle mass of 1500kg.

• 제어로봇시스템학회:학술대회논문집
• /
• 2004.08a
• /
• pp.342-345
• /
• 2004

An efficient hybrid ARQ scheme based on the rate compatible block turbo codes has been proposed, and its performance has been analyzed. System efficiency is improved by means of adaptive rate code transmission using channel information, trading off bit rate for channel codes, with resulting energy saving. The rate adaptation scheme improves power efficiency while keeping packet delay minimized. On the other hand, power dependant strategies reduce power consumption. Simulation results show that the benefits obtained are very encouraging. The modified hybrid ARQ schemes with the channel information and efficient retransmission structures highly improve the throughput performance in the satellite communication system. Therefore, proposed schemes could be used in future communication systems.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.7 no.5
• /
• pp.949-966
• /
• 2013

Recently, Wireless Body Area Network (WBAN) has promise to revolutionize human daily life. The need for multiple sensors and constant monitoring lead these systems to be energy hungry and expensive with short operating lifetimes. In this paper, we offer a review of existing work of WBAN and focus on energy-aware management in it. We emphasize that nodes computation, wireless communication, topology deployment and energy scavenging are main domains for making a long-lived WBAN. We study the popular power management technique Dynamic Voltage and Frequency Scaling (DVFS) and identify the impact of slack time in Dynamic Power Management (DPM), and finally propose an enhanced dynamic power management method to schedule scaled jobs at slack time with the goal of saving energy and keeping system reliability. Theoretical and experimental evaluations exhibit the effectiveness and efficiency of the proposed method.

• Proceedings of the KIPE Conference
• /
• 1997.07a
• /
• pp.216-221
• /
• 1997

At present, high frequency electronic ballast are widely used to drive the fluorescent lamp at high frequency for improving light quality. The electronic ballast mainly consist of an inverter stage with a load resonant circuit. This paper derives a lamp model consist of a voltage equation and a current equation. The proposed model is useful for an engineer to determine circuits and to analyze the performance of electronic ballast with high frequency operation. Simulation with PSPICE and experimentator and the high power factor of the proposed topology.

• 한국신재생에너지학회:학술대회논문집
• /
• 2005.06a
• /
• pp.201-204
• /
• 2005

In this research, we have studied the development of dc-dc converter suitable for the driving of mobile instruments by using a dye-sensitized solar cell(DSC). We also have designed a interlocking circuit. The circuit makes power from DSC be saved in one battery and concurrently be discharged in the other battery. As this application, mobile devices like MP3, cellular phone are drived by using power from DSC during the daytime and they can be drived by using the saving energy of the daytime during the night. Besides, we designed dc-dc converter circuit to drive low power instruments by using NMOS switch and PMOS rectifier.